diff --git a/core/java/android/hardware/display/BrightnessChangeEvent.java b/core/java/android/hardware/display/BrightnessChangeEvent.java
index 3003607..0a08353 100644
--- a/core/java/android/hardware/display/BrightnessChangeEvent.java
+++ b/core/java/android/hardware/display/BrightnessChangeEvent.java
@@ -28,7 +28,7 @@
  */
 public final class BrightnessChangeEvent implements Parcelable {
     /** Brightness in nits */
-    public int brightness;
+    public float brightness;
 
     /** Timestamp of the change {@see System.currentTimeMillis()} */
     public long timeStamp;
@@ -58,7 +58,7 @@
     public int colorTemperature;
 
     /** Brightness level before slider adjustment */
-    public int lastBrightness;
+    public float lastBrightness;
 
     public BrightnessChangeEvent() {
     }
@@ -78,7 +78,7 @@
     }
 
     private BrightnessChangeEvent(Parcel source) {
-        brightness = source.readInt();
+        brightness = source.readFloat();
         timeStamp = source.readLong();
         packageName = source.readString();
         userId = source.readInt();
@@ -87,7 +87,7 @@
         batteryLevel = source.readFloat();
         nightMode = source.readBoolean();
         colorTemperature = source.readInt();
-        lastBrightness = source.readInt();
+        lastBrightness = source.readFloat();
     }
 
     public static final Creator<BrightnessChangeEvent> CREATOR =
@@ -107,7 +107,7 @@
 
     @Override
     public void writeToParcel(Parcel dest, int flags) {
-        dest.writeInt(brightness);
+        dest.writeFloat(brightness);
         dest.writeLong(timeStamp);
         dest.writeString(packageName);
         dest.writeInt(userId);
@@ -116,6 +116,6 @@
         dest.writeFloat(batteryLevel);
         dest.writeBoolean(nightMode);
         dest.writeInt(colorTemperature);
-        dest.writeInt(lastBrightness);
+        dest.writeFloat(lastBrightness);
     }
 }
diff --git a/core/java/android/hardware/display/DisplayManager.java b/core/java/android/hardware/display/DisplayManager.java
index 7de667d..97e9b9c 100644
--- a/core/java/android/hardware/display/DisplayManager.java
+++ b/core/java/android/hardware/display/DisplayManager.java
@@ -628,13 +628,6 @@
     }
 
     /**
-     * @hide STOPSHIP - remove when adaptive brightness accepts curves.
-     */
-    public void setBrightness(int brightness) {
-        mGlobal.setBrightness(brightness);
-    }
-
-    /**
      * Sets the global display brightness configuration.
      *
      * @hide
diff --git a/core/java/android/hardware/display/DisplayManagerGlobal.java b/core/java/android/hardware/display/DisplayManagerGlobal.java
index bf4cc1d..cbb5a7d 100644
--- a/core/java/android/hardware/display/DisplayManagerGlobal.java
+++ b/core/java/android/hardware/display/DisplayManagerGlobal.java
@@ -476,18 +476,6 @@
     }
 
     /**
-     * Set brightness but don't add a BrightnessChangeEvent
-     * STOPSHIP remove when adaptive brightness accepts curves.
-     */
-    public void setBrightness(int brightness) {
-        try {
-            mDm.setBrightness(brightness);
-        } catch (RemoteException ex) {
-            throw ex.rethrowFromSystemServer();
-        }
-    }
-
-    /**
      * Sets the global brightness configuration for a given user.
      *
      * @hide
diff --git a/core/java/android/hardware/display/DisplayManagerInternal.java b/core/java/android/hardware/display/DisplayManagerInternal.java
index cd551bd..3f6dd2e 100644
--- a/core/java/android/hardware/display/DisplayManagerInternal.java
+++ b/core/java/android/hardware/display/DisplayManagerInternal.java
@@ -222,6 +222,11 @@
         // set by the user as opposed to being programmatically controlled by apps.
         public boolean brightnessSetByUser;
 
+        // Set to true if screenBrightness or screenAutoBrightnessAdjustment are being set
+        // temporarily. This is typically set while the user has their finger on the brightness
+        // control, before they've selected the final brightness value.
+        public boolean brightnessIsTemporary;
+
         // If true, enables automatic brightness control.
         public boolean useAutoBrightness;
 
@@ -280,6 +285,7 @@
             screenAutoBrightnessAdjustment = other.screenAutoBrightnessAdjustment;
             screenLowPowerBrightnessFactor = other.screenLowPowerBrightnessFactor;
             brightnessSetByUser = other.brightnessSetByUser;
+            brightnessIsTemporary = other.brightnessIsTemporary;
             useAutoBrightness = other.useAutoBrightness;
             blockScreenOn = other.blockScreenOn;
             lowPowerMode = other.lowPowerMode;
@@ -303,6 +309,7 @@
                     && screenLowPowerBrightnessFactor
                     == other.screenLowPowerBrightnessFactor
                     && brightnessSetByUser == other.brightnessSetByUser
+                    && brightnessIsTemporary == other.brightnessIsTemporary
                     && useAutoBrightness == other.useAutoBrightness
                     && blockScreenOn == other.blockScreenOn
                     && lowPowerMode == other.lowPowerMode
@@ -324,6 +331,7 @@
                     + ", screenAutoBrightnessAdjustment=" + screenAutoBrightnessAdjustment
                     + ", screenLowPowerBrightnessFactor=" + screenLowPowerBrightnessFactor
                     + ", brightnessSetByUser=" + brightnessSetByUser
+                    + ", brightnessIsTemporary=" + brightnessIsTemporary
                     + ", useAutoBrightness=" + useAutoBrightness
                     + ", blockScreenOn=" + blockScreenOn
                     + ", lowPowerMode=" + lowPowerMode
diff --git a/core/java/android/hardware/display/IDisplayManager.aidl b/core/java/android/hardware/display/IDisplayManager.aidl
index 8afae6e..61c42e1 100644
--- a/core/java/android/hardware/display/IDisplayManager.aidl
+++ b/core/java/android/hardware/display/IDisplayManager.aidl
@@ -87,10 +87,6 @@
     // Requires BRIGHTNESS_SLIDER_USAGE permission.
     ParceledListSlice getBrightnessEvents(String callingPackage);
 
-    // STOPSHIP remove when adaptive brightness code is updated to accept curves.
-    // Requires BRIGHTNESS_SLIDER_USAGE permission.
-    void setBrightness(int brightness);
-
     // Sets the global brightness configuration for a given user. Requires
     // CONFIGURE_DISPLAY_BRIGHTNESS, and INTERACT_ACROSS_USER if the user being configured is not
     // the same as the calling user.
diff --git a/core/res/res/values/config.xml b/core/res/res/values/config.xml
index dc791cf..fd05bb4 100644
--- a/core/res/res/values/config.xml
+++ b/core/res/res/values/config.xml
@@ -1302,8 +1302,8 @@
 
          If this is defined then:
             - config_autoBrightnessLcdBacklightValues should not be defined
-            - config_screenBrightnessMinimumNits must be defined
-            - config_screenBrightnessMaximumNits must be defined
+            - config_screenBrightnessNits must be defined
+            - config_screenBrightnessBacklight must be defined
 
          This array should have size one greater than the size of the config_autoBrightnessLevels
          array. The brightness values must be non-negative and non-decreasing. This must be
@@ -1347,28 +1347,23 @@
         <item>200</item>
     </integer-array>
 
-    <!-- The minimum brightness of the display in nits. On OLED displays this should be measured
-         with an all white image while the display is fully on and the backlight is set to
-         config_screenBrightnessSettingMinimum or config_screenBrightnessSettingDark, whichever
-         is darker.
+    <!-- An array describing the screen's backlight values corresponding to the brightness
+         values in the config_screenBrightnessNits array.
 
-         If this and config_screenBrightnessMinimumNits are set, then the display's brightness
-         range is assumed to be linear between
-         (config_screenBrightnessSettingMinimum, config_screenBrightnessMinimumNits) and
-         (config_screenBrightnessSettingMaximum, config_screenBrightnessMaximumNits). -->
-    <item name="config_screenBrightnessMinimumNits" format="float" type="dimen">-1.0</item>
+         This array should be equal in size to config_screenBrightnessBacklight. -->
+    <integer-array name="config_screenBrightnessBacklight">
+    </integer-array>
 
-    <!-- The maximum brightness of the display in nits. On OLED displays this should be measured
-         with an all white image while the display is fully on and the "backlight" is set to
-         config_screenBrightnessSettingMaximum. Note that this value should *not* reflect the
-         maximum brightness value for any high brightness modes but only the maximum brightness
-         value obtainable in a sustainable manner.
+    <!-- An array of floats describing the screen brightness in nits corresponding to the backlight
+         values in the config_screenBrightnessBacklight array.  On OLED displays these  values
+         should be measured with an all white image while the display is in the fully on state.
+         Note that this value should *not* reflect the maximum brightness value for any high
+         brightness modes but only the maximum brightness value obtainable in a sustainable manner.
 
-         If this and config_screenBrightnessMinimumNits are set to something non-negative, then the
-         display's brightness range is assumed to be linear between
-         (config_screenBrightnessSettingMinimum, config_screenBrightnessMaximumNits) and
-         (config_screenBrightnessSettingMaximum, config_screenBrightnessMaximumNits). -->
-    <item name="config_screenBrightnessMaximumNits" format="float" type="dimen">-1.0</item>
+         This array should be equal in size to config_screenBrightnessBacklight -->
+    <array name="config_screenBrightnessNits">
+    </array>
+
 
     <!-- Array of ambient lux threshold values. This is used for determining hysteresis constraint
          values by calculating the index to use for lookup and then setting the constraint value
diff --git a/core/res/res/values/symbols.xml b/core/res/res/values/symbols.xml
index 4b758be..4343ba0 100644
--- a/core/res/res/values/symbols.xml
+++ b/core/res/res/values/symbols.xml
@@ -3197,7 +3197,7 @@
   <java-symbol type="string" name="global_action_logout" />
   <java-symbol type="drawable" name="ic_logout" />
 
-  <java-symbol type="dimen" name="config_screenBrightnessMinimumNits" />
-  <java-symbol type="dimen" name="config_screenBrightnessMaximumNits" />
   <java-symbol type="array" name="config_autoBrightnessDisplayValuesNits" />
+  <java-symbol type="array" name="config_screenBrightnessBacklight" />
+  <java-symbol type="array" name="config_screenBrightnessNits" />
 </resources>
diff --git a/services/core/java/com/android/server/display/BrightnessMappingStrategy.java b/services/core/java/com/android/server/display/BrightnessMappingStrategy.java
index 3b9d40f..0b62907 100644
--- a/services/core/java/com/android/server/display/BrightnessMappingStrategy.java
+++ b/services/core/java/com/android/server/display/BrightnessMappingStrategy.java
@@ -17,6 +17,8 @@
 package com.android.server.display;
 
 import android.annotation.Nullable;
+import android.content.res.Resources;
+import android.content.res.TypedArray;
 import android.hardware.display.BrightnessConfiguration;
 import android.os.PowerManager;
 import android.util.MathUtils;
@@ -41,11 +43,30 @@
     private static final boolean DEBUG = false;
 
     @Nullable
-    public static BrightnessMappingStrategy create(
-            float[] luxLevels, int[] brightnessLevelsBacklight, float[] brightnessLevelsNits,
-            float[] nitsRange, int[] backlightRange) {
+    public static BrightnessMappingStrategy create(Resources resources) {
+        float[] luxLevels = getLuxLevels(resources.getIntArray(
+                com.android.internal.R.array.config_autoBrightnessLevels));
+        int[] brightnessLevelsBacklight = resources.getIntArray(
+                com.android.internal.R.array.config_autoBrightnessLcdBacklightValues);
+        float[] brightnessLevelsNits = getFloatArray(resources.obtainTypedArray(
+                com.android.internal.R.array.config_autoBrightnessDisplayValuesNits));
+
+        float[] nitsRange = getFloatArray(resources.obtainTypedArray(
+                com.android.internal.R.array.config_screenBrightnessNits));
+        int[] backlightRange = resources.getIntArray(
+                com.android.internal.R.array.config_screenBrightnessBacklight);
+
         if (isValidMapping(nitsRange, backlightRange)
                 && isValidMapping(luxLevels, brightnessLevelsNits)) {
+            int minimumBacklight = resources.getInteger(
+                    com.android.internal.R.integer.config_screenBrightnessSettingMinimum);
+            int maximumBacklight = resources.getInteger(
+                    com.android.internal.R.integer.config_screenBrightnessSettingMaximum);
+            if (backlightRange[0] > minimumBacklight
+                    || backlightRange[backlightRange.length - 1] < maximumBacklight) {
+                Slog.w(TAG, "Screen brightness mapping does not cover whole range of available"
+                        + " backlight values, autobrightness functionality may be impaired.");
+            }
             BrightnessConfiguration.Builder builder = new BrightnessConfiguration.Builder();
             builder.setCurve(luxLevels, brightnessLevelsNits);
             return new PhysicalMappingStrategy(builder.build(), nitsRange, backlightRange);
@@ -56,6 +77,25 @@
         }
     }
 
+    private static float[] getLuxLevels(int[] lux) {
+        // The first control point is implicit and always at 0 lux.
+        float[] levels = new float[lux.length + 1];
+        for (int i = 0; i < lux.length; i++) {
+            levels[i + 1] = (float) lux[i];
+        }
+        return levels;
+    }
+
+    private static float[] getFloatArray(TypedArray array) {
+        final int N = array.length();
+        float[] vals = new float[N];
+        for (int i = 0; i < N; i++) {
+            vals[i] = array.getFloat(i, -1.0f);
+        }
+        array.recycle();
+        return vals;
+    }
+
     private static boolean isValidMapping(float[] x, float[] y) {
         if (x == null || y == null || x.length == 0 || y.length == 0) {
             return false;
@@ -124,10 +164,17 @@
      * brightness and 0 is the display at minimum brightness.
      *
      * @param lux The current ambient brightness in lux.
-     * @return The desired brightness of the display compressed to the range [0, 1.0].
+     * @return The desired brightness of the display normalized to the range [0, 1.0].
      */
     public abstract float getBrightness(float lux);
 
+    /**
+     * Gets the display's brightness in nits for the given backlight value.
+     *
+     * Returns -1.0f if there's no available mapping for the backlight to nits.
+     */
+    public abstract float getNits(int backlight);
+
     public abstract void dump(PrintWriter pw);
 
     private static float normalizeAbsoluteBrightness(int brightness) {
@@ -186,6 +233,11 @@
         }
 
         @Override
+        public float getNits(int backlight) {
+            return -1.0f;
+        }
+
+        @Override
         public void dump(PrintWriter pw) {
             pw.println("SimpleMappingStrategy");
             pw.println("  mSpline=" + mSpline);
@@ -209,7 +261,11 @@
 
         // A spline mapping from nits to the corresponding backlight value, normalized to the range
         // [0, 1.0].
-        private final Spline mBacklightSpline;
+        private final Spline mNitsToBacklightSpline;
+
+        // A spline mapping from the device's backlight value, normalized to the range [0, 1.0], to
+        // a brightness in nits.
+        private final Spline mBacklightToNitsSpline;
 
         // The default brightness configuration.
         private final BrightnessConfiguration mDefaultConfig;
@@ -227,19 +283,18 @@
 
             // Setup the backlight spline
             final int N = nits.length;
-            float[] x = new float[N];
-            float[] y = new float[N];
+            float[] normalizedBacklight = new float[N];
             for (int i = 0; i < N; i++) {
-                x[i] = nits[i];
-                y[i] = normalizeAbsoluteBrightness(backlight[i]);
+                normalizedBacklight[i] = normalizeAbsoluteBrightness(backlight[i]);
             }
 
-            mBacklightSpline = Spline.createSpline(x, y);
+            mNitsToBacklightSpline = Spline.createSpline(nits, normalizedBacklight);
+            mBacklightToNitsSpline = Spline.createSpline(normalizedBacklight, nits);
             if (DEBUG) {
-                Slog.d(TAG, "Backlight spline: " + mBacklightSpline);
+                Slog.d(TAG, "Backlight spline: " + mNitsToBacklightSpline);
                 for (float v = 1f; v < nits[nits.length - 1] * 1.25f; v *= 1.25f) {
                     Slog.d(TAG, String.format(
-                                "  %7.1f: %7.1f", v, mBacklightSpline.interpolate(v)));
+                                "  %7.1f: %7.1f", v, mNitsToBacklightSpline.interpolate(v)));
                 }
             }
 
@@ -275,7 +330,12 @@
 
         @Override
         public float getBrightness(float lux) {
-            return mBacklightSpline.interpolate(mBrightnessSpline.interpolate(lux));
+            return mNitsToBacklightSpline.interpolate(mBrightnessSpline.interpolate(lux));
+        }
+
+        @Override
+        public float getNits(int backlight) {
+            return mBacklightToNitsSpline.interpolate(normalizeAbsoluteBrightness(backlight));
         }
 
         @Override
@@ -283,7 +343,7 @@
             pw.println("PhysicalMappingStrategy");
             pw.println("  mConfig=" + mConfig);
             pw.println("  mBrightnessSpline=" + mBrightnessSpline);
-            pw.println("  mBacklightSpline=" + mBacklightSpline);
+            pw.println("  mNitsToBacklightSpline=" + mNitsToBacklightSpline);
         }
     }
 }
diff --git a/services/core/java/com/android/server/display/BrightnessTracker.java b/services/core/java/com/android/server/display/BrightnessTracker.java
index 42247f9..cbb1c01 100644
--- a/services/core/java/com/android/server/display/BrightnessTracker.java
+++ b/services/core/java/com/android/server/display/BrightnessTracker.java
@@ -24,7 +24,6 @@
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.pm.ParceledListSlice;
-import android.database.ContentObserver;
 import android.hardware.Sensor;
 import android.hardware.SensorEvent;
 import android.hardware.SensorEventListener;
@@ -34,6 +33,8 @@
 import android.os.BatteryManager;
 import android.os.Environment;
 import android.os.Handler;
+import android.os.Looper;
+import android.os.Message;
 import android.os.PowerManager;
 import android.os.RemoteException;
 import android.os.SystemClock;
@@ -88,7 +89,7 @@
 
     private static final String TAG_EVENTS = "events";
     private static final String TAG_EVENT = "event";
-    private static final String ATTR_BRIGHTNESS = "brightness";
+    private static final String ATTR_NITS = "nits";
     private static final String ATTR_TIMESTAMP = "timestamp";
     private static final String ATTR_PACKAGE_NAME = "packageName";
     private static final String ATTR_USER = "user";
@@ -97,7 +98,10 @@
     private static final String ATTR_BATTERY_LEVEL = "batteryLevel";
     private static final String ATTR_NIGHT_MODE = "nightMode";
     private static final String ATTR_COLOR_TEMPERATURE = "colorTemperature";
-    private static final String ATTR_LAST_BRIGHTNESS = "lastBrightness";
+    private static final String ATTR_LAST_NITS = "lastNits";
+
+    private static final int MSG_BACKGROUND_START = 0;
+    private static final int MSG_BRIGHTNESS_CHANGED = 1;
 
     // Lock held while accessing mEvents, is held while writing events to flash.
     private final Object mEventsLock = new Object();
@@ -113,9 +117,7 @@
     private final Context mContext;
     private final ContentResolver mContentResolver;
     private Handler mBgHandler;
-    // mSettingsObserver, mBroadcastReceiver and mSensorListener should only be used on
-    // the mBgHandler thread.
-    private SettingsObserver mSettingsObserver;
+    // mBroadcastReceiver and mSensorListener should only be used on the mBgHandler thread.
     private BroadcastReceiver mBroadcastReceiver;
     private SensorListener mSensorListener;
 
@@ -126,9 +128,9 @@
     @GuardedBy("mDataCollectionLock")
     private float mLastBatteryLevel = Float.NaN;
     @GuardedBy("mDataCollectionLock")
-    private int mIgnoreBrightness = -1;
+    private float mLastBrightness = -1;
     @GuardedBy("mDataCollectionLock")
-    private int mLastBrightness = -1;
+    private boolean mStarted;
 
     private final Injector mInjector;
 
@@ -144,33 +146,31 @@
         }
     }
 
-    /** Start listening for brightness slider events */
-    public void start() {
+    /**
+     * Start listening for brightness slider events
+     *
+     * @param brightness the initial screen brightness
+     */
+    public void start(float initialBrightness) {
         if (DEBUG) {
             Slog.d(TAG, "Start");
         }
-        mBgHandler = mInjector.getBackgroundHandler();
+        mBgHandler = new TrackerHandler(mInjector.getBackgroundHandler().getLooper());
         mUserManager = mContext.getSystemService(UserManager.class);
 
-        mBgHandler.post(() -> backgroundStart());
+        mBgHandler.obtainMessage(MSG_BACKGROUND_START, (Float) initialBrightness).sendToTarget();
     }
 
-    private void backgroundStart() {
+    private void backgroundStart(float initialBrightness) {
         readEvents();
 
-        mLastBrightness = mInjector.getSystemIntForUser(mContentResolver,
-                Settings.System.SCREEN_BRIGHTNESS, -1,
-                UserHandle.USER_CURRENT);
-
         mSensorListener = new SensorListener();
 
+
         if (mInjector.isInteractive(mContext)) {
             mInjector.registerSensorListener(mContext, mSensorListener, mBgHandler);
         }
 
-        mSettingsObserver = new SettingsObserver(mBgHandler);
-        mInjector.registerBrightnessObserver(mContentResolver, mSettingsObserver);
-
         final IntentFilter intentFilter = new IntentFilter();
         intentFilter.addAction(Intent.ACTION_SHUTDOWN);
         intentFilter.addAction(Intent.ACTION_BATTERY_CHANGED);
@@ -180,6 +180,10 @@
         mInjector.registerReceiver(mContext, mBroadcastReceiver, intentFilter);
 
         mInjector.scheduleIdleJob(mContext);
+        synchronized (mDataCollectionLock) {
+            mLastBrightness = initialBrightness;
+            mStarted = true;
+        }
     }
 
     /** Stop listening for events */
@@ -188,10 +192,14 @@
         if (DEBUG) {
             Slog.d(TAG, "Stop");
         }
+        mBgHandler.removeMessages(MSG_BACKGROUND_START);
         mInjector.unregisterSensorListener(mContext, mSensorListener);
         mInjector.unregisterReceiver(mContext, mBroadcastReceiver);
-        mInjector.unregisterBrightnessObserver(mContext, mSettingsObserver);
         mInjector.cancelIdleJob(mContext);
+
+        synchronized (mDataCollectionLock) {
+            mStarted = false;
+        }
     }
 
     /**
@@ -220,40 +228,45 @@
         return new ParceledListSlice<>(out);
     }
 
-    /** Sets brightness without logging the brightness change event */
-    public void setBrightness(int brightness, int userId) {
-        synchronized (mDataCollectionLock) {
-            mIgnoreBrightness = brightness;
-        }
-        mInjector.putSystemIntForUser(mContentResolver, Settings.System.SCREEN_BRIGHTNESS,
-                brightness, userId);
-    }
-
     public void persistEvents() {
         scheduleWriteEvents();
     }
 
-    private void handleBrightnessChanged() {
+    /**
+     * Notify the BrightnessTracker that the user has changed the brightness of the display.
+     */
+    public void notifyBrightnessChanged(float brightness, boolean userInitiated) {
         if (DEBUG) {
-            Slog.d(TAG, "Brightness change");
+            Slog.d(TAG, String.format("notifyBrightnessChanged(brightness=%f, userInitiated=%b)",
+                        brightness, userInitiated));
         }
-        final BrightnessChangeEvent event = new BrightnessChangeEvent();
-        event.timeStamp = mInjector.currentTimeMillis();
+        Message m = mBgHandler.obtainMessage(MSG_BRIGHTNESS_CHANGED,
+                userInitiated ? 1 : 0, 0 /*unused*/, (Float) brightness);
+        m.sendToTarget();
+    }
 
-        int brightness = mInjector.getSystemIntForUser(mContentResolver,
-                Settings.System.SCREEN_BRIGHTNESS, -1,
-                UserHandle.USER_CURRENT);
-
+    private void handleBrightnessChanged(float brightness, boolean userInitiated) {
+        final BrightnessChangeEvent event;
         synchronized (mDataCollectionLock) {
-            int previousBrightness = mLastBrightness;
-            mLastBrightness = brightness;
-
-            if (brightness == -1 || brightness == mIgnoreBrightness) {
-                // Notified of brightness change but no setting or self change so ignore.
-                mIgnoreBrightness = -1;
+            if (!mStarted) {
+                // Not currently gathering brightness change information
                 return;
             }
 
+            float previousBrightness = mLastBrightness;
+            mLastBrightness = brightness;
+
+            if (!userInitiated) {
+                // We want to record what current brightness is so that we know what the user
+                // changed it from, but if it wasn't user initiated then we don't want to record it
+                // as a BrightnessChangeEvent.
+                return;
+            }
+
+
+            event = new BrightnessChangeEvent();
+            event.timeStamp = mInjector.currentTimeMillis();
+
             final int readingCount = mLastSensorReadings.size();
             if (readingCount == 0) {
                 // No sensor data so ignore this.
@@ -386,7 +399,7 @@
             if (userSerialNo != -1 && toWrite[i].timeStamp > timeCutOff) {
                 mEvents.append(toWrite[i]);
                 out.startTag(null, TAG_EVENT);
-                out.attribute(null, ATTR_BRIGHTNESS, Integer.toString(toWrite[i].brightness));
+                out.attribute(null, ATTR_NITS, Float.toString(toWrite[i].brightness));
                 out.attribute(null, ATTR_TIMESTAMP, Long.toString(toWrite[i].timeStamp));
                 out.attribute(null, ATTR_PACKAGE_NAME, toWrite[i].packageName);
                 out.attribute(null, ATTR_USER, Integer.toString(userSerialNo));
@@ -394,8 +407,8 @@
                 out.attribute(null, ATTR_NIGHT_MODE, Boolean.toString(toWrite[i].nightMode));
                 out.attribute(null, ATTR_COLOR_TEMPERATURE, Integer.toString(
                         toWrite[i].colorTemperature));
-                out.attribute(null, ATTR_LAST_BRIGHTNESS,
-                        Integer.toString(toWrite[i].lastBrightness));
+                out.attribute(null, ATTR_LAST_NITS,
+                        Float.toString(toWrite[i].lastBrightness));
                 StringBuilder luxValues = new StringBuilder();
                 StringBuilder luxTimestamps = new StringBuilder();
                 for (int j = 0; j < toWrite[i].luxValues.length; ++j) {
@@ -446,8 +459,8 @@
                 if (TAG_EVENT.equals(tag)) {
                     BrightnessChangeEvent event = new BrightnessChangeEvent();
 
-                    String brightness = parser.getAttributeValue(null, ATTR_BRIGHTNESS);
-                    event.brightness = Integer.parseInt(brightness);
+                    String brightness = parser.getAttributeValue(null, ATTR_NITS);
+                    event.brightness = Float.parseFloat(brightness);
                     String timestamp = parser.getAttributeValue(null, ATTR_TIMESTAMP);
                     event.timeStamp = Long.parseLong(timestamp);
                     event.packageName = parser.getAttributeValue(null, ATTR_PACKAGE_NAME);
@@ -460,8 +473,8 @@
                     String colorTemperature =
                             parser.getAttributeValue(null, ATTR_COLOR_TEMPERATURE);
                     event.colorTemperature = Integer.parseInt(colorTemperature);
-                    String lastBrightness = parser.getAttributeValue(null, ATTR_LAST_BRIGHTNESS);
-                    event.lastBrightness = Integer.parseInt(lastBrightness);
+                    String lastBrightness = parser.getAttributeValue(null, ATTR_LAST_NITS);
+                    event.lastBrightness = Float.parseFloat(lastBrightness);
 
                     String luxValue = parser.getAttributeValue(null, ATTR_LUX);
                     String luxTimestamp = parser.getAttributeValue(null, ATTR_LUX_TIMESTAMPS);
@@ -582,22 +595,6 @@
         }
     }
 
-    private final class SettingsObserver extends ContentObserver {
-        public SettingsObserver(Handler handler) {
-            super(handler);
-        }
-
-        @Override
-        public void onChange(boolean selfChange, Uri uri) {
-            if (DEBUG) {
-                Slog.v(TAG, "settings change " + uri);
-            }
-            // Self change is based on observer passed to notifyObserver, SettingsProvider
-            // passes null so no changes are self changes.
-            handleBrightnessChanged();
-        }
-    }
-
     private final class Receiver extends BroadcastReceiver {
         @Override
         public void onReceive(Context context, Intent intent) {
@@ -623,6 +620,24 @@
         }
     }
 
+    private final class TrackerHandler extends Handler {
+        public TrackerHandler(Looper looper) {
+            super(looper, null, true /*async*/);
+        }
+        public void handleMessage(Message msg) {
+            switch (msg.what) {
+                case MSG_BACKGROUND_START:
+                    backgroundStart((float)msg.obj /*initial brightness*/);
+                    break;
+                case MSG_BRIGHTNESS_CHANGED:
+                    float newBrightness = (float) msg.obj;
+                    boolean userInitiatedChange = (msg.arg1 == 1);
+                    handleBrightnessChanged(newBrightness, userInitiatedChange);
+                    break;
+            }
+        }
+    }
+
     @VisibleForTesting
     static class Injector {
         public void registerSensorListener(Context context,
@@ -638,18 +653,6 @@
             sensorManager.unregisterListener(sensorListener);
         }
 
-        public void registerBrightnessObserver(ContentResolver resolver,
-                ContentObserver settingsObserver) {
-            resolver.registerContentObserver(Settings.System.getUriFor(
-                    Settings.System.SCREEN_BRIGHTNESS),
-                    false, settingsObserver, UserHandle.USER_ALL);
-        }
-
-        public void unregisterBrightnessObserver(Context context,
-                ContentObserver settingsObserver) {
-            context.getContentResolver().unregisterContentObserver(settingsObserver);
-        }
-
         public void registerReceiver(Context context,
                 BroadcastReceiver receiver, IntentFilter filter) {
             context.registerReceiver(receiver, filter);
@@ -664,16 +667,6 @@
             return BackgroundThread.getHandler();
         }
 
-        public int getSystemIntForUser(ContentResolver resolver, String setting, int defaultValue,
-                int userId) {
-            return Settings.System.getIntForUser(resolver, setting, defaultValue, userId);
-        }
-
-        public void putSystemIntForUser(ContentResolver resolver, String setting, int value,
-                int userId) {
-            Settings.System.putIntForUser(resolver, setting, value, userId);
-        }
-
         public int getSecureIntForUser(ContentResolver resolver, String setting, int defaultValue,
                 int userId) {
             return Settings.Secure.getIntForUser(resolver, setting, defaultValue, userId);
diff --git a/services/core/java/com/android/server/display/DisplayManagerService.java b/services/core/java/com/android/server/display/DisplayManagerService.java
index 9b97934..02e4fe0 100644
--- a/services/core/java/com/android/server/display/DisplayManagerService.java
+++ b/services/core/java/com/android/server/display/DisplayManagerService.java
@@ -270,8 +270,6 @@
 
     private final Injector mInjector;
 
-    private final BrightnessTracker mBrightnessTracker;
-
     public DisplayManagerService(Context context) {
         this(context, new Injector());
     }
@@ -290,7 +288,6 @@
 
         PowerManager pm = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);
         mGlobalDisplayBrightness = pm.getDefaultScreenBrightnessSetting();
-        mBrightnessTracker = new BrightnessTracker(context, null);
         mCurrentUserId = UserHandle.USER_SYSTEM;
     }
 
@@ -1339,9 +1336,6 @@
 
             pw.println();
             mPersistentDataStore.dump(pw);
-
-            pw.println();
-            mBrightnessTracker.dump(pw);
         }
     }
 
@@ -1418,10 +1412,6 @@
                     break;
                 }
 
-                case MSG_REGISTER_BRIGHTNESS_TRACKER:
-                    mBrightnessTracker.start();
-                    break;
-
                 case MSG_LOAD_BRIGHTNESS_CONFIGURATION:
                     loadBrightnessConfiguration();
                     break;
@@ -1833,22 +1823,9 @@
             final int userId = UserHandle.getUserId(callingUid);
             final long token = Binder.clearCallingIdentity();
             try {
-                return mBrightnessTracker.getEvents(userId, hasUsageStats);
-            } finally {
-                Binder.restoreCallingIdentity(token);
-            }
-        }
-
-        @Override // Binder call
-        public void setBrightness(int brightness) {
-            // STOPSHIP - remove when adaptive brightness controller accepts curves.
-            mContext.enforceCallingOrSelfPermission(
-                    Manifest.permission.BRIGHTNESS_SLIDER_USAGE,
-                    "Permission to set brightness.");
-            int userId = UserHandle.getUserId(Binder.getCallingUid());
-            final long token = Binder.clearCallingIdentity();
-            try {
-                mBrightnessTracker.setBrightness(brightness, userId);
+                synchronized (mSyncRoot) {
+                    return mDisplayPowerController.getBrightnessEvents(userId, hasUsageStats);
+                }
             } finally {
                 Binder.restoreCallingIdentity(token);
             }
@@ -2028,7 +2005,9 @@
 
         @Override
         public void persistBrightnessSliderEvents() {
-            mBrightnessTracker.persistEvents();
+            synchronized (mSyncRoot) {
+                mDisplayPowerController.persistBrightnessSliderEvents();
+            }
         }
     }
 }
diff --git a/services/core/java/com/android/server/display/DisplayPowerController.java b/services/core/java/com/android/server/display/DisplayPowerController.java
index a2d9548..e5a4b0a 100644
--- a/services/core/java/com/android/server/display/DisplayPowerController.java
+++ b/services/core/java/com/android/server/display/DisplayPowerController.java
@@ -24,13 +24,16 @@
 
 import android.animation.Animator;
 import android.animation.ObjectAnimator;
+import android.annotation.Nullable;
+import android.annotation.UserIdInt;
 import android.content.Context;
+import android.content.pm.ParceledListSlice;
 import android.content.res.Resources;
-import android.content.res.TypedArray;
 import android.hardware.Sensor;
 import android.hardware.SensorEvent;
 import android.hardware.SensorEventListener;
 import android.hardware.SensorManager;
+import android.hardware.display.BrightnessChangeEvent;
 import android.hardware.display.BrightnessConfiguration;
 import android.hardware.display.DisplayManagerInternal.DisplayPowerCallbacks;
 import android.hardware.display.DisplayManagerInternal.DisplayPowerRequest;
@@ -96,7 +99,6 @@
     private static final int MSG_SCREEN_ON_UNBLOCKED = 3;
     private static final int MSG_SCREEN_OFF_UNBLOCKED = 4;
     private static final int MSG_CONFIGURE_BRIGHTNESS = 5;
-    private static final int MSG_USER_SWITCH = 6;
 
     private static final int PROXIMITY_UNKNOWN = -1;
     private static final int PROXIMITY_NEGATIVE = 0;
@@ -151,9 +153,6 @@
     // The dim screen brightness.
     private final int mScreenBrightnessDimConfig;
 
-    // The minimum screen brightness to use in a very dark room.
-    private final int mScreenBrightnessDarkConfig;
-
     // The minimum allowed brightness.
     private final int mScreenBrightnessRangeMinimum;
 
@@ -261,6 +260,13 @@
     private long mScreenOnBlockStartRealTime;
     private long mScreenOffBlockStartRealTime;
 
+    // The last brightness that was set by the user and not temporary. Set to -1 when a brightness
+    // has yet to be recorded.
+    private int mLastBrightness;
+    // The last auto brightness adjustment that was set by the user and not temporary. Set to
+    // Float.NaN when an auto-brightness adjustment hasn't been recorded yet.
+    private float mLastAutoBrightnessAdjustment;
+
     // Screen state we reported to policy. Must be one of REPORTED_TO_POLICY_SCREEN_* fields.
     private int mReportedScreenStateToPolicy;
 
@@ -289,6 +295,10 @@
     // The controller for the automatic brightness level.
     private AutomaticBrightnessController mAutomaticBrightnessController;
 
+    // The mapper between ambient lux, display backlight values, and display brightness.
+    @Nullable
+    private BrightnessMappingStrategy mBrightnessMapper;
+
     // The default brightness configuration. Used for whenever we don't have a valid brightness
     // configuration set. This is typically seen with users that don't have a brightness
     // configuration that's different from the default.
@@ -302,6 +312,9 @@
     private ObjectAnimator mColorFadeOffAnimator;
     private RampAnimator<DisplayPowerState> mScreenBrightnessRampAnimator;
 
+    // Tracker for brightness changes
+    private final BrightnessTracker mBrightnessTracker;
+
     /**
      * Creates the display power controller.
      */
@@ -309,6 +322,7 @@
             DisplayPowerCallbacks callbacks, Handler handler,
             SensorManager sensorManager, DisplayBlanker blanker) {
         mHandler = new DisplayControllerHandler(handler.getLooper());
+        mBrightnessTracker = new BrightnessTracker(context, null);
         mCallbacks = callbacks;
 
         mBatteryStats = BatteryStatsService.getService();
@@ -327,23 +341,8 @@
         mScreenBrightnessDimConfig = clampAbsoluteBrightness(resources.getInteger(
                 com.android.internal.R.integer.config_screenBrightnessDim));
 
-        mScreenBrightnessDarkConfig = clampAbsoluteBrightness(resources.getInteger(
-                com.android.internal.R.integer.config_screenBrightnessDark));
-        if (mScreenBrightnessDarkConfig > mScreenBrightnessDimConfig) {
-            Slog.w(TAG, "Expected config_screenBrightnessDark ("
-                    + mScreenBrightnessDarkConfig + ") to be less than or equal to "
-                    + "config_screenBrightnessDim (" + mScreenBrightnessDimConfig + ").");
-        }
-        if (mScreenBrightnessDarkConfig > screenBrightnessSettingMinimum) {
-            Slog.w(TAG, "Expected config_screenBrightnessDark ("
-                    + mScreenBrightnessDarkConfig + ") to be less than or equal to "
-                    + "config_screenBrightnessSettingMinimum ("
-                    + screenBrightnessSettingMinimum + ").");
-        }
-
-        int screenBrightnessRangeMinimum = Math.min(Math.min(
-                screenBrightnessSettingMinimum, mScreenBrightnessDimConfig),
-                mScreenBrightnessDarkConfig);
+        mScreenBrightnessRangeMinimum =
+                Math.min(screenBrightnessSettingMinimum, mScreenBrightnessDimConfig);
 
         mScreenBrightnessRangeMaximum = clampAbsoluteBrightness(resources.getInteger(
                     com.android.internal.R.integer.config_screenBrightnessSettingMaximum));
@@ -362,18 +361,6 @@
                 com.android.internal.R.bool.config_skipScreenOnBrightnessRamp);
 
         if (mUseSoftwareAutoBrightnessConfig) {
-            float[] luxLevels = getLuxLevels(resources.getIntArray(
-                    com.android.internal.R.array.config_autoBrightnessLevels));
-            int[] backlightValues = resources.getIntArray(
-                    com.android.internal.R.array.config_autoBrightnessLcdBacklightValues);
-            float[] brightnessValuesNits = getFloatArray(resources.obtainTypedArray(
-                    com.android.internal.R.array.config_autoBrightnessDisplayValuesNits));
-
-            final float screenMinimumNits = resources.getFloat(
-                    com.android.internal.R.dimen.config_screenBrightnessMinimumNits);
-            final float screenMaximumNits = resources.getFloat(
-                    com.android.internal.R.dimen.config_screenBrightnessMaximumNits);
-
             final float dozeScaleFactor = resources.getFraction(
                     com.android.internal.R.fraction.config_screenAutoBrightnessDozeScaleFactor,
                     1, 1);
@@ -413,31 +400,13 @@
                         + "config_autoBrightnessLightSensorRate (" + lightSensorRate + ").");
             }
 
-            if (backlightValues != null && backlightValues.length > 0) {
-                final int bottom = backlightValues[0];
-                if (mScreenBrightnessDarkConfig > bottom) {
-                    Slog.w(TAG, "config_screenBrightnessDark (" + mScreenBrightnessDarkConfig
-                            + ") should be less than or equal to the first value of "
-                            + "config_autoBrightnessLcdBacklightValues ("
-                            + bottom + ").");
-                }
-                if (bottom < screenBrightnessRangeMinimum) {
-                    screenBrightnessRangeMinimum = bottom;
-                }
-            }
-
-            float[] nitsRange = { screenMinimumNits, screenMaximumNits };
-            int[] backlightRange = { screenBrightnessRangeMinimum, mScreenBrightnessRangeMaximum };
-
-            BrightnessMappingStrategy mapper = BrightnessMappingStrategy.create(
-                    luxLevels, backlightValues, brightnessValuesNits,
-                    nitsRange, backlightRange);
-            if (mapper != null) {
+            mBrightnessMapper = BrightnessMappingStrategy.create(resources);
+            if (mBrightnessMapper != null) {
                 mAutomaticBrightnessController = new AutomaticBrightnessController(this,
-                        handler.getLooper(), sensorManager, mapper, lightSensorWarmUpTimeConfig,
-                        screenBrightnessRangeMinimum, mScreenBrightnessRangeMaximum,
-                        dozeScaleFactor, lightSensorRate, initialLightSensorRate,
-                        brighteningLightDebounce, darkeningLightDebounce,
+                        handler.getLooper(), sensorManager, mBrightnessMapper,
+                        lightSensorWarmUpTimeConfig, mScreenBrightnessRangeMinimum,
+                        mScreenBrightnessRangeMaximum, dozeScaleFactor, lightSensorRate,
+                        initialLightSensorRate, brighteningLightDebounce, darkeningLightDebounce,
                         autoBrightnessResetAmbientLuxAfterWarmUp, ambientLightHorizon,
                         autoBrightnessAdjustmentMaxGamma, dynamicHysteresis);
             } else {
@@ -445,9 +414,6 @@
             }
         }
 
-        mScreenBrightnessRangeMinimum = screenBrightnessRangeMinimum;
-
-
         mColorFadeEnabled = !ActivityManager.isLowRamDeviceStatic();
         mColorFadeFadesConfig = resources.getBoolean(
                 com.android.internal.R.bool.config_animateScreenLights);
@@ -466,25 +432,8 @@
             }
         }
 
-    }
-
-    private static float[] getLuxLevels(int[] lux) {
-        // The first control point is implicit and always at 0 lux.
-        float[] levels = new float[lux.length + 1];
-        for (int i = 0; i < lux.length; i++) {
-            levels[i + 1] = (float) lux[i];
-        }
-        return levels;
-    }
-
-    private static float[] getFloatArray(TypedArray array) {
-        final int N = array.length();
-        float[] vals = new float[N];
-        for (int i = 0; i < N; i++) {
-            vals[i] = array.getFloat(i, -1.0f);
-        }
-        array.recycle();
-        return vals;
+        mLastBrightness = -1;
+        mLastAutoBrightnessAdjustment = Float.NaN;
     }
 
     /**
@@ -495,6 +444,23 @@
     }
 
     /**
+     * Get the {@link BrightnessChangeEvent}s for the specified user.
+     * @param userId userId to fetch data for
+     * @param includePackage if false will null out the package name in events
+     */
+    public ParceledListSlice<BrightnessChangeEvent> getBrightnessEvents(
+            @UserIdInt int userId, boolean includePackage) {
+        return mBrightnessTracker.getEvents(userId, includePackage);
+    }
+
+    /**
+     * Persist the brightness slider events to disk.
+     */
+    public void persistBrightnessSliderEvents() {
+        mBrightnessTracker.persistEvents();
+    }
+
+    /**
      * Requests a new power state.
      * The controller makes a copy of the provided object and then
      * begins adjusting the power state to match what was requested.
@@ -588,6 +554,12 @@
         } catch (RemoteException ex) {
             // same process
         }
+
+        // Initialize all of the brightness tracking state
+        final float brightness = getNits(mPowerState.getScreenBrightness());
+        if (brightness >= 0.0f) {
+            mBrightnessTracker.start(brightness);
+        }
     }
 
     private final Animator.AnimatorListener mAnimatorListener = new Animator.AnimatorListener() {
@@ -722,16 +694,32 @@
             brightness = PowerManager.BRIGHTNESS_OFF;
         }
 
-        // Configure auto-brightness.
-        boolean autoBrightnessEnabled = false;
-        if (mAutomaticBrightnessController != null) {
-            final boolean autoBrightnessEnabledInDoze =
-                    mAllowAutoBrightnessWhileDozingConfig && Display.isDozeState(state);
-            autoBrightnessEnabled = mPowerRequest.useAutoBrightness
+
+        final boolean autoBrightnessEnabledInDoze =
+                mAllowAutoBrightnessWhileDozingConfig && Display.isDozeState(state);
+        final boolean autoBrightnessEnabled = mPowerRequest.useAutoBrightness
                     && (state == Display.STATE_ON || autoBrightnessEnabledInDoze)
-                    && brightness < 0;
-            final boolean userInitiatedChange = autoBrightnessAdjustmentChanged
-                    && mPowerRequest.brightnessSetByUser;
+                    && brightness < 0
+                    && mAutomaticBrightnessController != null;
+        final boolean brightnessAdjustmentChanged =
+                !Float.isNaN(mLastAutoBrightnessAdjustment)
+                && mPowerRequest.screenAutoBrightnessAdjustment != mLastAutoBrightnessAdjustment;
+        final boolean brightnessChanged = mLastBrightness >= 0
+                && mPowerRequest.screenBrightness != mLastBrightness;
+
+        // Update the last set brightness values.
+        final boolean userInitiatedChange;
+        if (mPowerRequest.brightnessSetByUser && !mPowerRequest.brightnessIsTemporary) {
+            userInitiatedChange = autoBrightnessEnabled && brightnessAdjustmentChanged
+                    || !autoBrightnessEnabled && brightnessChanged;
+            mLastBrightness = mPowerRequest.screenBrightness;
+            mLastAutoBrightnessAdjustment = mPowerRequest.screenAutoBrightnessAdjustment;
+        } else {
+            userInitiatedChange = false;
+        }
+
+        // Configure auto-brightness.
+        if (mAutomaticBrightnessController != null) {
             mAutomaticBrightnessController.configure(autoBrightnessEnabled,
                     mBrightnessConfiguration, mPowerRequest.screenAutoBrightnessAdjustment,
                     state != Display.STATE_ON, userInitiatedChange);
@@ -854,6 +842,13 @@
                 animateScreenBrightness(brightness,
                         slowChange ? mBrightnessRampRateSlow : mBrightnessRampRateFast);
             }
+
+            final float brightnessInNits = getNits(brightness);
+            if (!mPowerRequest.brightnessIsTemporary && brightnessInNits >= 0.0f) {
+                // We only want to track changes made by the user and on devices that can actually
+                // map the display backlight values into a physical brightness unit.
+                mBrightnessTracker.notifyBrightnessChanged(brightnessInNits, userInitiatedChange);
+            }
         }
 
         // Determine whether the display is ready for use in the newly requested state.
@@ -1312,6 +1307,14 @@
         mHandler.post(mOnStateChangedRunnable);
     }
 
+    private float getNits(int backlight) {
+        if (mBrightnessMapper != null) {
+            return mBrightnessMapper.getNits(backlight);
+        } else {
+            return -1.0f;
+        }
+    }
+
     private final Runnable mOnStateChangedRunnable = new Runnable() {
         @Override
         public void run() {
@@ -1362,7 +1365,6 @@
         pw.println("Display Power Controller Configuration:");
         pw.println("  mScreenBrightnessDozeConfig=" + mScreenBrightnessDozeConfig);
         pw.println("  mScreenBrightnessDimConfig=" + mScreenBrightnessDimConfig);
-        pw.println("  mScreenBrightnessDarkConfig=" + mScreenBrightnessDarkConfig);
         pw.println("  mScreenBrightnessRangeMinimum=" + mScreenBrightnessRangeMinimum);
         pw.println("  mScreenBrightnessRangeMaximum=" + mScreenBrightnessRangeMaximum);
         pw.println("  mUseSoftwareAutoBrightnessConfig=" + mUseSoftwareAutoBrightnessConfig);
@@ -1383,7 +1385,6 @@
         pw.println("Display Power Controller Thread State:");
         pw.println("  mPowerRequest=" + mPowerRequest);
         pw.println("  mWaitingForNegativeProximity=" + mWaitingForNegativeProximity);
-
         pw.println("  mProximitySensor=" + mProximitySensor);
         pw.println("  mProximitySensorEnabled=" + mProximitySensorEnabled);
         pw.println("  mProximityThreshold=" + mProximityThreshold);
@@ -1392,6 +1393,8 @@
         pw.println("  mPendingProximityDebounceTime="
                 + TimeUtils.formatUptime(mPendingProximityDebounceTime));
         pw.println("  mScreenOffBecauseOfProximity=" + mScreenOffBecauseOfProximity);
+        pw.println("  mLastBrightness=" + mLastBrightness);
+        pw.println("  mLastAutoBrightnessAdjustment=" + mLastAutoBrightnessAdjustment);
         pw.println("  mAppliedAutoBrightness=" + mAppliedAutoBrightness);
         pw.println("  mAppliedDimming=" + mAppliedDimming);
         pw.println("  mAppliedLowPower=" + mAppliedLowPower);
@@ -1420,6 +1423,10 @@
             mAutomaticBrightnessController.dump(pw);
         }
 
+        if (mBrightnessTracker != null) {
+            pw.println();
+            mBrightnessTracker.dump(pw);
+        }
     }
 
     private static String proximityToString(int state) {
diff --git a/services/core/java/com/android/server/power/PowerManagerService.java b/services/core/java/com/android/server/power/PowerManagerService.java
index bc7f2e6..86b22bb 100644
--- a/services/core/java/com/android/server/power/PowerManagerService.java
+++ b/services/core/java/com/android/server/power/PowerManagerService.java
@@ -2452,6 +2452,7 @@
             float screenAutoBrightnessAdjustment = 0.0f;
             boolean autoBrightness = (mScreenBrightnessModeSetting ==
                     Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC);
+            boolean brightnessIsTemporary = false;
             if (!mBootCompleted) {
                 // Keep the brightness steady during boot. This requires the
                 // bootloader brightness and the default brightness to be identical.
@@ -2466,6 +2467,7 @@
                 brightnessSetByUser = false;
             } else if (isValidBrightness(mTemporaryScreenBrightnessSettingOverride)) {
                 screenBrightness = mTemporaryScreenBrightnessSettingOverride;
+                brightnessIsTemporary = true;
             } else if (isValidBrightness(mScreenBrightnessSetting)) {
                 screenBrightness = mScreenBrightnessSetting;
             }
@@ -2475,6 +2477,7 @@
                         mTemporaryScreenAutoBrightnessAdjustmentSettingOverride)) {
                     screenAutoBrightnessAdjustment =
                             mTemporaryScreenAutoBrightnessAdjustmentSettingOverride;
+                    brightnessIsTemporary = true;
                 } else if (isValidAutoBrightnessAdjustment(
                         mScreenAutoBrightnessAdjustmentSetting)) {
                     screenAutoBrightnessAdjustment = mScreenAutoBrightnessAdjustmentSetting;
@@ -2490,6 +2493,7 @@
             mDisplayPowerRequest.screenAutoBrightnessAdjustment =
                     screenAutoBrightnessAdjustment;
             mDisplayPowerRequest.brightnessSetByUser = brightnessSetByUser;
+            mDisplayPowerRequest.brightnessIsTemporary = brightnessIsTemporary;
             mDisplayPowerRequest.useAutoBrightness = autoBrightness;
             mDisplayPowerRequest.useProximitySensor = shouldUseProximitySensorLocked();
             mDisplayPowerRequest.boostScreenBrightness = shouldBoostScreenBrightness();
diff --git a/services/tests/servicestests/src/com/android/server/display/BrightnessMappingStrategyTest.java b/services/tests/servicestests/src/com/android/server/display/BrightnessMappingStrategyTest.java
index 2629b12..5105f4e 100644
--- a/services/tests/servicestests/src/com/android/server/display/BrightnessMappingStrategyTest.java
+++ b/services/tests/servicestests/src/com/android/server/display/BrightnessMappingStrategyTest.java
@@ -20,7 +20,13 @@
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.anyFloat;
+import static org.mockito.ArgumentMatchers.anyInt;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
+import android.content.res.Resources;
+import android.content.res.TypedArray;
 import android.os.PowerManager;
 import android.support.test.filters.SmallTest;
 import android.support.test.runner.AndroidJUnit4;
@@ -35,18 +41,18 @@
 @RunWith(AndroidJUnit4.class)
 public class BrightnessMappingStrategyTest {
 
-    private static final float[] LUX_LEVELS = {
-        0f,
-        5f,
-        20f,
-        40f,
-        100f,
-        325f,
-        600f,
-        1250f,
-        2200f,
-        4000f,
-        5000f
+    private static final int[] LUX_LEVELS = {
+        0,
+        5,
+        20,
+        40,
+        100,
+        325,
+        600,
+        1250,
+        2200,
+        4000,
+        5000
     };
 
     private static final float[] DISPLAY_LEVELS_NITS = {
@@ -80,11 +86,13 @@
     private static final float[] DISPLAY_RANGE_NITS = { 2.685f, 478.5f };
     private static final int[] BACKLIGHT_RANGE = { 1, 255 };
 
+    private static final float[] EMPTY_FLOAT_ARRAY = new float[0];
+    private static final int[] EMPTY_INT_ARRAY = new int[0];
+
     @Test
     public void testSimpleStrategyMappingAtControlPoints() {
-        BrightnessMappingStrategy simple = BrightnessMappingStrategy.create(
-                LUX_LEVELS, DISPLAY_LEVELS_BACKLIGHT,
-                null /*brightnessLevelsNits*/, null /*nitsRange*/, null /*backlightRange*/);
+        Resources res = createResources(LUX_LEVELS, DISPLAY_LEVELS_BACKLIGHT);
+        BrightnessMappingStrategy simple = BrightnessMappingStrategy.create(res);
         assertNotNull("BrightnessMappingStrategy should not be null", simple);
         for (int i = 0; i < LUX_LEVELS.length; i++) {
             final float expectedLevel =
@@ -96,9 +104,8 @@
 
     @Test
     public void testSimpleStrategyMappingBetweenControlPoints() {
-        BrightnessMappingStrategy simple = BrightnessMappingStrategy.create(
-                LUX_LEVELS, DISPLAY_LEVELS_BACKLIGHT,
-                null /*brightnessLevelsNits*/, null /*nitsRange*/, null /*backlightRange*/);
+        Resources res = createResources(LUX_LEVELS, DISPLAY_LEVELS_BACKLIGHT);
+        BrightnessMappingStrategy simple = BrightnessMappingStrategy.create(res);
         assertNotNull("BrightnessMappingStrategy should not be null", simple);
         for (int i = 1; i < LUX_LEVELS.length; i++) {
             final float lux = (LUX_LEVELS[i - 1] + LUX_LEVELS[i]) / 2;
@@ -111,9 +118,9 @@
 
     @Test
     public void testPhysicalStrategyMappingAtControlPoints() {
-        BrightnessMappingStrategy physical = BrightnessMappingStrategy.create(
-                LUX_LEVELS, null /*brightnessLevelsBacklight*/,
-                DISPLAY_LEVELS_NITS, DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        Resources res = createResources(LUX_LEVELS, DISPLAY_LEVELS_NITS,
+                DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        BrightnessMappingStrategy physical = BrightnessMappingStrategy.create(res);
         assertNotNull("BrightnessMappingStrategy should not be null", physical);
         for (int i = 0; i < LUX_LEVELS.length; i++) {
             final float expectedLevel = DISPLAY_LEVELS_NITS[i] / DISPLAY_RANGE_NITS[1];
@@ -124,9 +131,9 @@
 
     @Test
     public void testPhysicalStrategyMappingBetweenControlPoints() {
-        BrightnessMappingStrategy physical = BrightnessMappingStrategy.create(
-                LUX_LEVELS, null /*brightnessLevelsBacklight*/,
-                DISPLAY_LEVELS_NITS, DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        Resources res = createResources(LUX_LEVELS, DISPLAY_LEVELS_NITS,
+                DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        BrightnessMappingStrategy physical = BrightnessMappingStrategy.create(res);
         assertNotNull("BrightnessMappingStrategy should not be null", physical);
         Spline backlightToBrightness =
                 Spline.createSpline(toFloatArray(BACKLIGHT_RANGE), DISPLAY_RANGE_NITS);
@@ -141,82 +148,79 @@
 
     @Test
     public void testDefaultStrategyIsPhysical() {
-        BrightnessMappingStrategy strategy = BrightnessMappingStrategy.create(
-                LUX_LEVELS, DISPLAY_LEVELS_BACKLIGHT,
+        Resources res = createResources(LUX_LEVELS, DISPLAY_LEVELS_BACKLIGHT,
                 DISPLAY_LEVELS_NITS, DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        BrightnessMappingStrategy strategy = BrightnessMappingStrategy.create(res);
         assertTrue(strategy instanceof BrightnessMappingStrategy.PhysicalMappingStrategy);
     }
 
     @Test
     public void testNonStrictlyIncreasingLuxLevelsFails() {
-        final float[] lux = Arrays.copyOf(LUX_LEVELS, LUX_LEVELS.length);
+        final int[] lux = Arrays.copyOf(LUX_LEVELS, LUX_LEVELS.length);
         final int idx = lux.length / 2;
-        float tmp = lux[idx];
+        int tmp = lux[idx];
         lux[idx] = lux[idx+1];
         lux[idx+1] = tmp;
-        BrightnessMappingStrategy strategy = BrightnessMappingStrategy.create(
-                lux, null /*brightnessLevelsBacklight*/,
-                DISPLAY_LEVELS_NITS, DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        Resources res = createResources(lux, DISPLAY_LEVELS_NITS,
+                DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        BrightnessMappingStrategy strategy = BrightnessMappingStrategy.create(res);
         assertNull(strategy);
 
         // And make sure we get the same result even if it's monotone but not increasing.
         lux[idx] = lux[idx+1];
-        strategy = BrightnessMappingStrategy.create(
-                lux, null /*brightnessLevelsBacklight*/,
-                DISPLAY_LEVELS_NITS, DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        res = createResources(lux, DISPLAY_LEVELS_NITS, DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        strategy = BrightnessMappingStrategy.create(res);
         assertNull(strategy);
     }
 
     @Test
     public void testDifferentNumberOfControlPointValuesFails() {
         //Extra lux level
-        final float[] lux = Arrays.copyOf(LUX_LEVELS, LUX_LEVELS.length+1);
+        final int[] lux = Arrays.copyOf(LUX_LEVELS, LUX_LEVELS.length+1);
         // Make sure it's strictly increasing so that the only failure is the differing array
         // lengths
         lux[lux.length - 1] = lux[lux.length - 2] + 1;
-        BrightnessMappingStrategy strategy = BrightnessMappingStrategy.create(
-                lux, null /*brightnessLevelsBacklight*/,
-                DISPLAY_LEVELS_NITS, DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        Resources res = createResources(lux, DISPLAY_LEVELS_NITS,
+                DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        BrightnessMappingStrategy strategy = BrightnessMappingStrategy.create(res);
         assertNull(strategy);
 
-        strategy = BrightnessMappingStrategy.create(
-                lux, DISPLAY_LEVELS_BACKLIGHT,
-                null /*brightnessLevelsNits*/, null /*nitsRange*/, null /*backlightRange*/);
+        res = createResources(lux, DISPLAY_LEVELS_BACKLIGHT);
+        strategy = BrightnessMappingStrategy.create(res);
         assertNull(strategy);
 
         // Extra backlight level
         final int[] backlight = Arrays.copyOf(
                 DISPLAY_LEVELS_BACKLIGHT, DISPLAY_LEVELS_BACKLIGHT.length+1);
         backlight[backlight.length - 1] = backlight[backlight.length - 2] + 1;
-        strategy = BrightnessMappingStrategy.create(
-                LUX_LEVELS, backlight,
-                null /*brightnessLevelsNits*/, null /*nitsRange*/, null /*backlightRange*/);
+        res = createResources(LUX_LEVELS, backlight);
+        strategy = BrightnessMappingStrategy.create(res);
         assertNull(strategy);
 
         // Extra nits level
         final float[] nits = Arrays.copyOf(DISPLAY_RANGE_NITS, DISPLAY_LEVELS_NITS.length+1);
         nits[nits.length - 1] = nits[nits.length - 2] + 1;
-        strategy = BrightnessMappingStrategy.create(
-                LUX_LEVELS, null /*brightnessLevelsBacklight*/,
-                nits, DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        res = createResources(LUX_LEVELS, nits, DISPLAY_RANGE_NITS, BACKLIGHT_RANGE);
+        strategy = BrightnessMappingStrategy.create(res);
         assertNull(strategy);
     }
 
     @Test
     public void testPhysicalStrategyRequiresNitsMapping() {
-        BrightnessMappingStrategy physical = BrightnessMappingStrategy.create(
-                LUX_LEVELS, null /*brightnessLevelsBacklight*/,
-                DISPLAY_LEVELS_NITS, null, BACKLIGHT_RANGE);
+        Resources res = createResources(LUX_LEVELS, EMPTY_INT_ARRAY /*brightnessLevelsBacklight*/,
+                DISPLAY_LEVELS_NITS, EMPTY_FLOAT_ARRAY /*nitsRange*/, BACKLIGHT_RANGE);
+        BrightnessMappingStrategy physical = BrightnessMappingStrategy.create(res);
         assertNull(physical);
 
-        physical = BrightnessMappingStrategy.create(
-                LUX_LEVELS, null /*brightnessLevelsBacklight*/,
-                DISPLAY_LEVELS_NITS, DISPLAY_RANGE_NITS, null);
+        res = createResources(LUX_LEVELS, EMPTY_INT_ARRAY /*brightnessLevelsBacklight*/,
+                DISPLAY_LEVELS_NITS, DISPLAY_RANGE_NITS, EMPTY_INT_ARRAY /*backlightRange*/);
+        physical = BrightnessMappingStrategy.create(res);
         assertNull(physical);
 
-        physical = BrightnessMappingStrategy.create(
-                LUX_LEVELS, null /*brightnessLevelsBacklight*/,
-                DISPLAY_LEVELS_NITS, null, null);
+        res = createResources(LUX_LEVELS, EMPTY_INT_ARRAY /*brightnessLevelsBacklight*/,
+                DISPLAY_LEVELS_NITS, EMPTY_FLOAT_ARRAY /*nitsRange*/,
+                EMPTY_INT_ARRAY /*backlightRange*/);
+        physical = BrightnessMappingStrategy.create(res);
         assertNull(physical);
     }
 
@@ -227,4 +231,73 @@
         }
         return newVals;
     }
+
+    private Resources createResources(int[] luxLevels, int[] brightnessLevelsBacklight) {
+        return createResources(luxLevels, brightnessLevelsBacklight,
+                EMPTY_FLOAT_ARRAY /*brightnessLevelsNits*/, EMPTY_FLOAT_ARRAY /*nitsRange*/,
+                EMPTY_INT_ARRAY /*backlightRange*/);
+    }
+
+    private Resources createResources(int[] luxLevels, float[] brightnessLevelsNits,
+            float[] nitsRange, int[] backlightRange) {
+        return createResources(luxLevels, EMPTY_INT_ARRAY /*brightnessLevelsBacklight*/,
+                brightnessLevelsNits, nitsRange, backlightRange);
+    }
+
+    private Resources createResources(int[] luxLevels, int[] brightnessLevelsBacklight,
+            float[] brightnessLevelsNits, float[] nitsRange, int[] backlightRange) {
+        Resources mockResources = mock(Resources.class);
+        // For historical reasons, the lux levels resource implicitly defines the first point as 0,
+        // so we need to chop it off of the array the mock resource object returns.
+        int[] luxLevelsResource = Arrays.copyOfRange(luxLevels, 1, luxLevels.length);
+        when(mockResources.getIntArray(com.android.internal.R.array.config_autoBrightnessLevels))
+                .thenReturn(luxLevelsResource);
+
+        when(mockResources.getIntArray(
+                com.android.internal.R.array.config_autoBrightnessLcdBacklightValues))
+                .thenReturn(brightnessLevelsBacklight);
+
+        TypedArray mockBrightnessLevelNits = createFloatTypedArray(brightnessLevelsNits);
+        when(mockResources.obtainTypedArray(
+                com.android.internal.R.array.config_autoBrightnessDisplayValuesNits))
+                .thenReturn(mockBrightnessLevelNits);
+
+        TypedArray mockNitsRange = createFloatTypedArray(nitsRange);
+        when(mockResources.obtainTypedArray(
+                com.android.internal.R.array.config_screenBrightnessNits))
+                .thenReturn(mockNitsRange);
+
+        when(mockResources.getIntArray(
+                com.android.internal.R.array.config_screenBrightnessBacklight))
+                .thenReturn(backlightRange);
+
+        when(mockResources.getInteger(
+                com.android.internal.R.integer.config_screenBrightnessSettingMinimum))
+                .thenReturn(1);
+        when(mockResources.getInteger(
+                com.android.internal.R.integer.config_screenBrightnessSettingMaximum))
+                .thenReturn(255);
+        return mockResources;
+    }
+
+    private TypedArray createFloatTypedArray(float[] vals) {
+        TypedArray mockArray = mock(TypedArray.class);
+        when(mockArray.length()).thenAnswer(invocation -> {
+            return vals.length;
+        });
+        when(mockArray.getFloat(anyInt(), anyFloat())).thenAnswer(invocation -> {
+            final float def = (float) invocation.getArguments()[1];
+            if (vals == null) {
+                return def;
+            }
+            int idx = (int) invocation.getArguments()[0];
+            if (idx >= 0 && idx < vals.length) {
+                return vals[idx];
+            } else {
+                return def;
+            }
+        });
+        return mockArray;
+    }
+
 }
diff --git a/services/tests/servicestests/src/com/android/server/display/BrightnessTrackerTest.java b/services/tests/servicestests/src/com/android/server/display/BrightnessTrackerTest.java
index 926009e..08edd52 100644
--- a/services/tests/servicestests/src/com/android/server/display/BrightnessTrackerTest.java
+++ b/services/tests/servicestests/src/com/android/server/display/BrightnessTrackerTest.java
@@ -66,6 +66,8 @@
 @SmallTest
 @RunWith(AndroidJUnit4.class)
 public class BrightnessTrackerTest {
+    private static final float DEFAULT_INITIAL_BRIGHTNESS = 2.5f;
+    private static final float FLOAT_DELTA = 0.01f;
 
     private BrightnessTracker mTracker;
     private TestInjector mInjector;
@@ -98,7 +100,6 @@
         mInjector.mInteractive = false;
         startTracker(mTracker);
         assertNull(mInjector.mSensorListener);
-        assertNotNull(mInjector.mSettingsObserver);
         assertNotNull(mInjector.mBroadcastReceiver);
         assertTrue(mInjector.mIdleScheduled);
         Intent onIntent = new Intent();
@@ -119,7 +120,6 @@
 
         mTracker.stop();
         assertNull(mInjector.mSensorListener);
-        assertNull(mInjector.mSettingsObserver);
         assertNull(mInjector.mBroadcastReceiver);
         assertFalse(mInjector.mIdleScheduled);
     }
@@ -128,12 +128,10 @@
     public void testBrightnessEvent() {
         final int brightness = 20;
 
-        mInjector.mSystemIntSettings.put(Settings.System.SCREEN_BRIGHTNESS, brightness);
         startTracker(mTracker);
         mInjector.mSensorListener.onSensorChanged(createSensorEvent(1.0f));
         mInjector.incrementTime(TimeUnit.SECONDS.toMillis(2));
-        mInjector.mSettingsObserver.onChange(false, Settings.System.getUriFor(
-                Settings.System.SCREEN_BRIGHTNESS));
+        notifyBrightnessChanged(mTracker, brightness);
         List<BrightnessChangeEvent> events = mTracker.getEvents(0, true).getList();
         mTracker.stop();
 
@@ -141,10 +139,11 @@
         BrightnessChangeEvent event = events.get(0);
         assertEquals(mInjector.currentTimeMillis(), event.timeStamp);
         assertEquals(1, event.luxValues.length);
-        assertEquals(1.0f, event.luxValues[0], 0.1f);
+        assertEquals(1.0f, event.luxValues[0], FLOAT_DELTA);
         assertEquals(mInjector.currentTimeMillis() - TimeUnit.SECONDS.toMillis(2),
                 event.luxTimestamps[0]);
-        assertEquals(brightness, event.brightness);
+        assertEquals(brightness, event.brightness, FLOAT_DELTA);
+        assertEquals(DEFAULT_INITIAL_BRIGHTNESS, event.lastBrightness, FLOAT_DELTA);
 
         // System had no data so these should all be at defaults.
         assertEquals(Float.NaN, event.batteryLevel, 0.0);
@@ -154,21 +153,18 @@
 
     @Test
     public void testBrightnessFullPopulatedEvent() {
-        final int lastBrightness = 230;
+        final int initialBrightness = 230;
         final int brightness = 130;
 
-        mInjector.mSystemIntSettings.put(Settings.System.SCREEN_BRIGHTNESS, lastBrightness);
         mInjector.mSecureIntSettings.put(Settings.Secure.NIGHT_DISPLAY_ACTIVATED, 1);
         mInjector.mSecureIntSettings.put(Settings.Secure.NIGHT_DISPLAY_COLOR_TEMPERATURE, 3333);
 
-        startTracker(mTracker);
-        mInjector.mSystemIntSettings.put(Settings.System.SCREEN_BRIGHTNESS, brightness);
+        startTracker(mTracker, initialBrightness);
         mInjector.mBroadcastReceiver.onReceive(InstrumentationRegistry.getContext(),
                 batteryChangeEvent(30, 60));
         mInjector.mSensorListener.onSensorChanged(createSensorEvent(1000.0f));
         final long sensorTime = mInjector.currentTimeMillis();
-        mInjector.mSettingsObserver.onChange(false, Settings.System.getUriFor(
-                Settings.System.SCREEN_BRIGHTNESS));
+        notifyBrightnessChanged(mTracker, brightness);
         List<BrightnessChangeEvent> eventsNoPackage
                 = mTracker.getEvents(0, false).getList();
         List<BrightnessChangeEvent> events = mTracker.getEvents(0, true).getList();
@@ -179,9 +175,9 @@
         assertEquals(event.timeStamp, mInjector.currentTimeMillis());
         assertArrayEquals(new float[] {1000.0f}, event.luxValues, 0.01f);
         assertArrayEquals(new long[] {sensorTime}, event.luxTimestamps);
-        assertEquals(brightness, event.brightness);
-        assertEquals(lastBrightness, event.lastBrightness);
-        assertEquals(0.5, event.batteryLevel, 0.01);
+        assertEquals(brightness, event.brightness, FLOAT_DELTA);
+        assertEquals(initialBrightness, event.lastBrightness, FLOAT_DELTA);
+        assertEquals(0.5, event.batteryLevel, FLOAT_DELTA);
         assertTrue(event.nightMode);
         assertEquals(3333, event.colorTemperature);
         assertEquals("a.package", event.packageName);
@@ -192,45 +188,34 @@
     }
 
     @Test
-    public void testIgnoreSelfChange() {
+    public void testIgnoreAutomaticBrightnessChange() {
         final int initialBrightness = 30;
-        mInjector.mSystemIntSettings.put(Settings.System.SCREEN_BRIGHTNESS, initialBrightness);
-        startTracker(mTracker);
+        startTracker(mTracker, initialBrightness);
         mInjector.mSensorListener.onSensorChanged(createSensorEvent(1.0f));
         mInjector.incrementTime(TimeUnit.SECONDS.toMillis(1));
 
         final int systemUpdatedBrightness = 20;
-        mTracker.setBrightness(systemUpdatedBrightness, 0);
-        assertEquals(systemUpdatedBrightness,
-                (int) mInjector.mSystemIntSettings.get(Settings.System.SCREEN_BRIGHTNESS));
-        mInjector.mSettingsObserver.onChange(false, Settings.System.getUriFor(
-                Settings.System.SCREEN_BRIGHTNESS));
+        notifyBrightnessChanged(mTracker, systemUpdatedBrightness, false /*userInitiated*/);
         List<BrightnessChangeEvent> events = mTracker.getEvents(0, true).getList();
         // No events because we filtered out our change.
         assertEquals(0, events.size());
 
         final int firstUserUpdateBrightness = 20;
         // Then change comes from somewhere else so we shouldn't filter.
-        mInjector.mSystemIntSettings.put(Settings.System.SCREEN_BRIGHTNESS,
-                firstUserUpdateBrightness);
-        mInjector.mSettingsObserver.onChange(false, Settings.System.getUriFor(
-                Settings.System.SCREEN_BRIGHTNESS));
+        notifyBrightnessChanged(mTracker, firstUserUpdateBrightness);
 
         // and with a different brightness value.
         final int secondUserUpdateBrightness = 34;
-        mInjector.mSystemIntSettings.put(Settings.System.SCREEN_BRIGHTNESS,
-                secondUserUpdateBrightness);
-        mInjector.mSettingsObserver.onChange(false, Settings.System.getUriFor(
-                Settings.System.SCREEN_BRIGHTNESS));
+        notifyBrightnessChanged(mTracker, secondUserUpdateBrightness);
         events = mTracker.getEvents(0, true).getList();
 
         assertEquals(2, events.size());
         // First event is change from system update (20) to first user update (20)
-        assertEquals(systemUpdatedBrightness, events.get(0).lastBrightness);
-        assertEquals(firstUserUpdateBrightness, events.get(0).brightness);
+        assertEquals(systemUpdatedBrightness, events.get(0).lastBrightness, FLOAT_DELTA);
+        assertEquals(firstUserUpdateBrightness, events.get(0).brightness, FLOAT_DELTA);
         // Second event is from first to second user update.
-        assertEquals(firstUserUpdateBrightness, events.get(1).lastBrightness);
-        assertEquals(secondUserUpdateBrightness, events.get(1).brightness);
+        assertEquals(firstUserUpdateBrightness, events.get(1).lastBrightness, FLOAT_DELTA);
+        assertEquals(secondUserUpdateBrightness, events.get(1).brightness, FLOAT_DELTA);
 
         mTracker.stop();
     }
@@ -243,9 +228,7 @@
         for (int brightness = 0; brightness <= 255; ++brightness) {
             mInjector.mSensorListener.onSensorChanged(createSensorEvent(1.0f));
             mInjector.incrementTime(TimeUnit.SECONDS.toNanos(1));
-            mInjector.mSystemIntSettings.put(Settings.System.SCREEN_BRIGHTNESS, brightness);
-            mInjector.mSettingsObserver.onChange(false, Settings.System.getUriFor(
-                    Settings.System.SCREEN_BRIGHTNESS));
+            notifyBrightnessChanged(mTracker, brightness);
         }
         List<BrightnessChangeEvent> events = mTracker.getEvents(0, true).getList();
         mTracker.stop();
@@ -254,14 +237,13 @@
         assertEquals(100, events.size());
         for (int i = 0; i < events.size(); i++) {
             BrightnessChangeEvent event = events.get(i);
-            assertEquals(156 + i, event.brightness);
+            assertEquals(156 + i, event.brightness, FLOAT_DELTA);
         }
     }
 
     @Test
     public void testLimitedSensorEvents() {
         final int brightness = 20;
-        mInjector.mSystemIntSettings.put(Settings.System.SCREEN_BRIGHTNESS, brightness);
 
         startTracker(mTracker);
         // 20 Sensor events 1 second apart.
@@ -269,8 +251,7 @@
             mInjector.incrementTime(TimeUnit.SECONDS.toMillis(1));
             mInjector.mSensorListener.onSensorChanged(createSensorEvent(i + 1.0f));
         }
-        mInjector.mSettingsObserver.onChange(false, Settings.System.getUriFor(
-                Settings.System.SCREEN_BRIGHTNESS));
+        notifyBrightnessChanged(mTracker, 20);
         List<BrightnessChangeEvent> events = mTracker.getEvents(0, true).getList();
         mTracker.stop();
 
@@ -284,7 +265,7 @@
             assertEquals(event.luxTimestamps[11 - i],
                     mInjector.currentTimeMillis() - i * TimeUnit.SECONDS.toMillis(1));
         }
-        assertEquals(brightness, event.brightness);
+        assertEquals(brightness, event.brightness, FLOAT_DELTA);
     }
 
     @Test
@@ -298,25 +279,25 @@
         String eventFile =
                 "<?xml version='1.0' encoding='utf-8' standalone='yes' ?>\n"
                 + "<events>\n"
-                + "<event brightness=\"194\" timestamp=\""
+                + "<event nits=\"194.2\" timestamp=\""
                 + Long.toString(someTimeAgo) + "\" packageName=\""
                 + "com.example.app\" user=\"10\" "
-                + "lastBrightness=\"32\" "
+                + "lastNits=\"32.333\" "
                 + "batteryLevel=\"1.0\" nightMode=\"false\" colorTemperature=\"0\"\n"
                 + "lux=\"32.2,31.1\" luxTimestamps=\""
                 + Long.toString(someTimeAgo) + "," + Long.toString(someTimeAgo) + "\"/>"
-                + "<event brightness=\"71\" timestamp=\""
+                + "<event nits=\"71\" timestamp=\""
                 + Long.toString(someTimeAgo) + "\" packageName=\""
                 + "com.android.anapp\" user=\"11\" "
-                + "lastBrightness=\"32\" "
+                + "lastNits=\"32\" "
                 + "batteryLevel=\"0.5\" nightMode=\"true\" colorTemperature=\"3235\"\n"
                 + "lux=\"132.2,131.1\" luxTimestamps=\""
                 + Long.toString(someTimeAgo) + "," + Long.toString(someTimeAgo) + "\"/>"
                 // Event that is too old so shouldn't show up.
-                + "<event brightness=\"142\" timestamp=\""
+                + "<event nits=\"142\" timestamp=\""
                 + Long.toString(twoMonthsAgo) + "\" packageName=\""
                 + "com.example.app\" user=\"10\" "
-                + "lastBrightness=\"32\" "
+                + "lastNits=\"32\" "
                 + "batteryLevel=\"1.0\" nightMode=\"false\" colorTemperature=\"0\"\n"
                 + "lux=\"32.2,31.1\" luxTimestamps=\""
                 + Long.toString(twoMonthsAgo) + "," + Long.toString(twoMonthsAgo) + "\"/>"
@@ -326,27 +307,27 @@
         assertEquals(1, events.size());
         BrightnessChangeEvent event = events.get(0);
         assertEquals(someTimeAgo, event.timeStamp);
-        assertEquals(194, event.brightness);
-        assertArrayEquals(new float[] {32.2f, 31.1f}, event.luxValues, 0.01f);
+        assertEquals(194.2, event.brightness, FLOAT_DELTA);
+        assertArrayEquals(new float[] {32.2f, 31.1f}, event.luxValues, FLOAT_DELTA);
         assertArrayEquals(new long[] {someTimeAgo, someTimeAgo}, event.luxTimestamps);
-        assertEquals(32, event.lastBrightness);
+        assertEquals(32.333, event.lastBrightness, FLOAT_DELTA);
         assertEquals(0, event.userId);
         assertFalse(event.nightMode);
-        assertEquals(1.0f, event.batteryLevel, 0.01);
+        assertEquals(1.0f, event.batteryLevel, FLOAT_DELTA);
         assertEquals("com.example.app", event.packageName);
 
         events = tracker.getEvents(1, true).getList();
         assertEquals(1, events.size());
         event = events.get(0);
         assertEquals(someTimeAgo, event.timeStamp);
-        assertEquals(71, event.brightness);
-        assertArrayEquals(new float[] {132.2f, 131.1f}, event.luxValues, 0.01f);
+        assertEquals(71, event.brightness, FLOAT_DELTA);
+        assertArrayEquals(new float[] {132.2f, 131.1f}, event.luxValues, FLOAT_DELTA);
         assertArrayEquals(new long[] {someTimeAgo, someTimeAgo}, event.luxTimestamps);
-        assertEquals(32, event.lastBrightness);
+        assertEquals(32, event.lastBrightness, FLOAT_DELTA);
         assertEquals(1, event.userId);
         assertTrue(event.nightMode);
         assertEquals(3235, event.colorTemperature);
-        assertEquals(0.5f, event.batteryLevel, 0.01);
+        assertEquals(0.5f, event.batteryLevel, FLOAT_DELTA);
         assertEquals("com.android.anapp", event.packageName);
     }
 
@@ -370,7 +351,7 @@
         eventFile =
                 "<?xml version='1.0' encoding='utf-8' standalone='yes' ?>\n"
                         + "<events>\n"
-                        + "<event brightness=\"194\" timestamp=\"" + someTimeAgo + "\" packageName=\""
+                        + "<event nits=\"194\" timestamp=\"" + someTimeAgo + "\" packageName=\""
                         + "com.example.app\" user=\"10\" "
                         + "batteryLevel=\"0.7\" nightMode=\"false\" colorTemperature=\"0\" />\n"
                         + "</events>";
@@ -386,7 +367,6 @@
     public void testWriteThenRead() throws Exception {
         final int brightness = 20;
 
-        mInjector.mSystemIntSettings.put(Settings.System.SCREEN_BRIGHTNESS, brightness);
         mInjector.mSecureIntSettings.put(Settings.Secure.NIGHT_DISPLAY_ACTIVATED, 1);
         mInjector.mSecureIntSettings.put(Settings.Secure.NIGHT_DISPLAY_COLOR_TEMPERATURE, 3339);
 
@@ -399,8 +379,7 @@
         mInjector.mSensorListener.onSensorChanged(createSensorEvent(3000.0f));
         final long secondSensorTime = mInjector.currentTimeMillis();
         mInjector.incrementTime(TimeUnit.SECONDS.toMillis(3));
-        mInjector.mSettingsObserver.onChange(false, Settings.System.getUriFor(
-                Settings.System.SCREEN_BRIGHTNESS));
+        notifyBrightnessChanged(mTracker, brightness);
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
         mTracker.writeEventsLocked(baos);
         mTracker.stop();
@@ -414,10 +393,10 @@
 
         assertEquals(1, events.size());
         BrightnessChangeEvent event = events.get(0);
-        assertArrayEquals(new float[] {2000.0f, 3000.0f}, event.luxValues, 0.01f);
+        assertArrayEquals(new float[] {2000.0f, 3000.0f}, event.luxValues, FLOAT_DELTA);
         assertArrayEquals(new long[] {firstSensorTime, secondSensorTime}, event.luxTimestamps);
-        assertEquals(brightness, event.brightness);
-        assertEquals(0.3, event.batteryLevel, 0.01f);
+        assertEquals(brightness, event.brightness, FLOAT_DELTA);
+        assertEquals(0.3, event.batteryLevel, FLOAT_DELTA);
         assertTrue(event.nightMode);
         assertEquals(3339, event.colorTemperature);
     }
@@ -426,7 +405,6 @@
     public void testWritePrunesOldEvents() throws Exception {
         final int brightness = 20;
 
-        mInjector.mSystemIntSettings.put(Settings.System.SCREEN_BRIGHTNESS, brightness);
         mInjector.mSecureIntSettings.put(Settings.Secure.NIGHT_DISPLAY_ACTIVATED, 1);
         mInjector.mSecureIntSettings.put(Settings.Secure.NIGHT_DISPLAY_COLOR_TEMPERATURE, 3339);
 
@@ -437,14 +415,12 @@
         mInjector.incrementTime(TimeUnit.SECONDS.toMillis(1));
         mInjector.mSensorListener.onSensorChanged(createSensorEvent(2000.0f));
         final long sensorTime = mInjector.currentTimeMillis();
-        mInjector.mSettingsObserver.onChange(false, Settings.System.getUriFor(
-                Settings.System.SCREEN_BRIGHTNESS));
+        notifyBrightnessChanged(mTracker, brightness);
 
         // 31 days later
         mInjector.incrementTime(TimeUnit.DAYS.toMillis(31));
         mInjector.mSensorListener.onSensorChanged(createSensorEvent(3000.0f));
-        mInjector.mSettingsObserver.onChange(false, Settings.System.getUriFor(
-                Settings.System.SCREEN_BRIGHTNESS));
+        notifyBrightnessChanged(mTracker, brightness);
         final long eventTime = mInjector.currentTimeMillis();
 
         List<BrightnessChangeEvent> events = mTracker.getEvents(0, true).getList();
@@ -460,10 +436,10 @@
         assertEquals(eventTime, event.timeStamp);
 
         // We will keep one of the old sensor events because we keep 1 event outside the window.
-        assertArrayEquals(new float[] {2000.0f, 3000.0f}, event.luxValues, 0.01f);
+        assertArrayEquals(new float[] {2000.0f, 3000.0f}, event.luxValues, FLOAT_DELTA);
         assertArrayEquals(new long[] {sensorTime, eventTime}, event.luxTimestamps);
-        assertEquals(brightness, event.brightness);
-        assertEquals(0.3, event.batteryLevel, 0.01f);
+        assertEquals(brightness, event.brightness, FLOAT_DELTA);
+        assertEquals(0.3, event.batteryLevel, FLOAT_DELTA);
         assertTrue(event.nightMode);
         assertEquals(3339, event.colorTemperature);
     }
@@ -472,7 +448,7 @@
     public void testParcelUnParcel() {
         Parcel parcel = Parcel.obtain();
         BrightnessChangeEvent event = new BrightnessChangeEvent();
-        event.brightness = 23;
+        event.brightness = 23f;
         event.timeStamp = 345L;
         event.packageName = "com.example";
         event.userId = 12;
@@ -485,7 +461,7 @@
         event.batteryLevel = 0.7f;
         event.nightMode = false;
         event.colorTemperature = 345;
-        event.lastBrightness = 50;
+        event.lastBrightness = 50f;
 
         event.writeToParcel(parcel, 0);
         byte[] parceled = parcel.marshall();
@@ -497,16 +473,16 @@
 
         BrightnessChangeEvent event2 = BrightnessChangeEvent.CREATOR.createFromParcel(parcel);
         parcel.recycle();
-        assertEquals(event.brightness, event2.brightness);
+        assertEquals(event.brightness, event2.brightness, FLOAT_DELTA);
         assertEquals(event.timeStamp, event2.timeStamp);
         assertEquals(event.packageName, event2.packageName);
         assertEquals(event.userId, event2.userId);
-        assertArrayEquals(event.luxValues, event2.luxValues, 0.01f);
+        assertArrayEquals(event.luxValues, event2.luxValues, FLOAT_DELTA);
         assertArrayEquals(event.luxTimestamps, event2.luxTimestamps);
-        assertEquals(event.batteryLevel, event2.batteryLevel, 0.01f);
+        assertEquals(event.batteryLevel, event2.batteryLevel, FLOAT_DELTA);
         assertEquals(event.nightMode, event2.nightMode);
         assertEquals(event.colorTemperature, event2.colorTemperature);
-        assertEquals(event.lastBrightness, event2.lastBrightness);
+        assertEquals(event.lastBrightness, event2.lastBrightness, FLOAT_DELTA);
 
         parcel = Parcel.obtain();
         event.batteryLevel = Float.NaN;
@@ -518,7 +494,7 @@
         parcel.unmarshall(parceled, 0, parceled.length);
         parcel.setDataPosition(0);
         event2 = BrightnessChangeEvent.CREATOR.createFromParcel(parcel);
-        assertEquals(event.batteryLevel, event2.batteryLevel, 0.01f);
+        assertEquals(event.batteryLevel, event2.batteryLevel, FLOAT_DELTA);
     }
 
     private InputStream getInputStream(String data) {
@@ -550,7 +526,21 @@
     }
 
     private void startTracker(BrightnessTracker tracker) {
-        tracker.start();
+        startTracker(tracker, DEFAULT_INITIAL_BRIGHTNESS);
+    }
+
+    private void startTracker(BrightnessTracker tracker, float initialBrightness) {
+        tracker.start(initialBrightness);
+        mInjector.waitForHandler();
+    }
+
+    private void notifyBrightnessChanged(BrightnessTracker tracker, float brightness) {
+        notifyBrightnessChanged(tracker, brightness, true /*userInitiated*/);
+    }
+
+    private void notifyBrightnessChanged(BrightnessTracker tracker, float brightness,
+            boolean userInitiated) {
+        tracker.notifyBrightnessChanged(brightness, userInitiated);
         mInjector.waitForHandler();
     }
 
@@ -578,7 +568,6 @@
 
     private class TestInjector extends BrightnessTracker.Injector {
         SensorEventListener mSensorListener;
-        ContentObserver mSettingsObserver;
         BroadcastReceiver mBroadcastReceiver;
         Map<String, Integer> mSystemIntSettings = new HashMap<>();
         Map<String, Integer> mSecureIntSettings = new HashMap<>();
@@ -610,18 +599,6 @@
         }
 
         @Override
-        public void registerBrightnessObserver(ContentResolver resolver,
-                ContentObserver settingsObserver) {
-            mSettingsObserver = settingsObserver;
-        }
-
-        @Override
-        public void unregisterBrightnessObserver(Context context,
-                ContentObserver settingsObserver) {
-            mSettingsObserver = null;
-        }
-
-        @Override
         public void registerReceiver(Context context,
                 BroadcastReceiver shutdownReceiver, IntentFilter shutdownFilter) {
             mBroadcastReceiver = shutdownReceiver;
@@ -647,23 +624,6 @@
         }
 
         @Override
-        public int getSystemIntForUser(ContentResolver resolver, String setting, int defaultValue,
-                int userId) {
-            Integer value = mSystemIntSettings.get(setting);
-            if (value == null) {
-                return defaultValue;
-            } else {
-                return value;
-            }
-        }
-
-        @Override
-        public void putSystemIntForUser(ContentResolver resolver, String setting, int value,
-                int userId) {
-            mSystemIntSettings.put(setting, value);
-        }
-
-        @Override
         public int getSecureIntForUser(ContentResolver resolver, String setting, int defaultValue,
                 int userId) {
             Integer value = mSecureIntSettings.get(setting);