diff --git a/api/system-current.txt b/api/system-current.txt
index 339f40b..e9fc9d2 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -26957,7 +26957,6 @@
     method public android.metrics.LogMaker clearPackageName();
     method public android.metrics.LogMaker clearSubtype();
     method public android.metrics.LogMaker clearTaggedData(int);
-    method public android.metrics.LogMaker clearTimestamp();
     method public android.metrics.LogMaker clearType();
     method public void deserialize(java.lang.Object[]);
     method public int getCategory();
@@ -26965,6 +26964,7 @@
     method public java.lang.String getCounterName();
     method public int getCounterValue();
     method public java.lang.String getPackageName();
+    method public int getProcessId();
     method public int getSubtype();
     method public java.lang.Object getTaggedData(int);
     method public long getTimestamp();
@@ -26974,13 +26974,8 @@
     method public boolean isValidValue(java.lang.Object);
     method public java.lang.Object[] serialize();
     method public android.metrics.LogMaker setCategory(int);
-    method public android.metrics.LogMaker setCounterBucket(int);
-    method public android.metrics.LogMaker setCounterBucket(long);
-    method public android.metrics.LogMaker setCounterName(java.lang.String);
-    method public android.metrics.LogMaker setCounterValue(int);
     method public android.metrics.LogMaker setPackageName(java.lang.String);
     method public android.metrics.LogMaker setSubtype(int);
-    method public android.metrics.LogMaker setTimestamp(long);
     method public android.metrics.LogMaker setType(int);
   }
 
diff --git a/core/java/android/metrics/LogMaker.java b/core/java/android/metrics/LogMaker.java
index 612b135..60b27b4 100644
--- a/core/java/android/metrics/LogMaker.java
+++ b/core/java/android/metrics/LogMaker.java
@@ -46,8 +46,9 @@
 
     private SparseArray<Object> entries = new SparseArray();
 
-    public LogMaker(int mainCategory) {
-        setCategory(mainCategory);
+    /** @param category for the new LogMaker. */
+    public LogMaker(int category) {
+        setCategory(category);
     }
 
     /* Deserialize from the eventlog */
@@ -55,71 +56,133 @@
       deserialize(items);
     }
 
+    /** @param category to replace the existing setting. */
     public LogMaker setCategory(int category) {
         entries.put(MetricsEvent.RESERVED_FOR_LOGBUILDER_CATEGORY, category);
         return this;
     }
 
+    /** Set the category to unknown. */
     public LogMaker clearCategory() {
         entries.remove(MetricsEvent.RESERVED_FOR_LOGBUILDER_CATEGORY);
         return this;
     }
 
+    /** @param type to replace the existing setting. */
     public LogMaker setType(int type) {
         entries.put(MetricsEvent.RESERVED_FOR_LOGBUILDER_TYPE, type);
         return this;
     }
 
+    /** Set the type to unknown. */
     public LogMaker clearType() {
         entries.remove(MetricsEvent.RESERVED_FOR_LOGBUILDER_TYPE);
         return this;
     }
 
+    /** @param subtype to replace the existing setting. */
     public LogMaker setSubtype(int subtype) {
         entries.put(MetricsEvent.RESERVED_FOR_LOGBUILDER_SUBTYPE, subtype);
         return this;
     }
 
+    /** Set the subtype to 0. */
     public LogMaker clearSubtype() {
         entries.remove(MetricsEvent.RESERVED_FOR_LOGBUILDER_SUBTYPE);
         return this;
     }
 
+    /**
+     * This will be set by the system when the log is persisted.
+     * Client-supplied values will be ignored.
+     *
+     * @param timestamp to replace the existing settings.
+     * @hide
+     */
     public LogMaker setTimestamp(long timestamp) {
         entries.put(MetricsEvent.RESERVED_FOR_LOGBUILDER_TIMESTAMP, timestamp);
         return this;
     }
 
+    /** Remove the timestamp property.
+     * @hide
+     */
     public LogMaker clearTimestamp() {
         entries.remove(MetricsEvent.RESERVED_FOR_LOGBUILDER_TIMESTAMP);
         return this;
     }
 
+    /** @param packageName to replace the existing setting. */
     public LogMaker setPackageName(String packageName) {
         entries.put(MetricsEvent.RESERVED_FOR_LOGBUILDER_PACKAGENAME, packageName);
         return this;
     }
 
+    /** Remove the package name property. */
     public LogMaker clearPackageName() {
         entries.remove(MetricsEvent.RESERVED_FOR_LOGBUILDER_PACKAGENAME);
         return this;
     }
 
+    /**
+     * This will be set by the system when the log is persisted.
+     * Client-supplied values will be ignored.
+     *
+     * @param pid to replace the existing setting.
+     * @hide
+     */
+    public LogMaker setProcessId(int pid) {
+        entries.put(MetricsEvent.RESERVED_FOR_LOGBUILDER_PID, pid);
+        return this;
+    }
+
+    /** Remove the process ID property.
+     * @hide
+     */
+    public LogMaker clearProcessId() {
+        entries.remove(MetricsEvent.RESERVED_FOR_LOGBUILDER_PID);
+        return this;
+    }
+
+    /**
+     * The name of the counter or histogram.
+     * Only useful for counter or histogram category objects.
+     * @param name to replace the existing setting.
+     * @hide
+     */
     public LogMaker setCounterName(String name) {
         entries.put(MetricsEvent.RESERVED_FOR_LOGBUILDER_NAME, name);
         return this;
     }
 
+    /**
+     * The bucket label, expressed as an integer.
+     * Only useful for histogram category objects.
+     * @param bucket to replace the existing setting.
+     * @hide
+     */
     public LogMaker setCounterBucket(int bucket) {
         entries.put(MetricsEvent.RESERVED_FOR_LOGBUILDER_BUCKET, bucket);
         return this;
     }
 
+    /**
+     * The bucket label, expressed as a long integer.
+     * Only useful for histogram category objects.
+     * @param bucket to replace the existing setting.
+     * @hide
+     */
     public LogMaker setCounterBucket(long bucket) {
         entries.put(MetricsEvent.RESERVED_FOR_LOGBUILDER_BUCKET, bucket);
         return this;
     }
 
+    /**
+     * The value to increment the counter or bucket by.
+     * Only useful for counter and histogram category objects.
+     * @param value to replace the existing setting.
+     * @hide
+     */
     public LogMaker setCounterValue(int value) {
         entries.put(MetricsEvent.RESERVED_FOR_LOGBUILDER_VALUE, value);
         return this;
@@ -171,6 +234,7 @@
         return entries.get(tag);
     }
 
+    /** @return the category of the log, or unknown. */
     public int getCategory() {
         Object obj = entries.get(MetricsEvent.RESERVED_FOR_LOGBUILDER_CATEGORY);
         if (obj instanceof Integer) {
@@ -180,6 +244,7 @@
         }
     }
 
+    /** @return the type of the log, or unknwon. */
     public int getType() {
         Object obj = entries.get(MetricsEvent.RESERVED_FOR_LOGBUILDER_TYPE);
         if (obj instanceof Integer) {
@@ -189,6 +254,7 @@
         }
     }
 
+    /** @return the subtype of the log, or 0. */
     public int getSubtype() {
         Object obj = entries.get(MetricsEvent.RESERVED_FOR_LOGBUILDER_SUBTYPE);
         if (obj instanceof Integer) {
@@ -198,6 +264,7 @@
         }
     }
 
+    /** @return the timestamp of the log.or 0 */
     public long getTimestamp() {
         Object obj = entries.get(MetricsEvent.RESERVED_FOR_LOGBUILDER_TIMESTAMP);
         if (obj instanceof Long) {
@@ -207,6 +274,7 @@
         }
     }
 
+    /** @return the package name of the log, or null. */
     public String getPackageName() {
         Object obj = entries.get(MetricsEvent.RESERVED_FOR_LOGBUILDER_PACKAGENAME);
         if (obj instanceof String) {
@@ -216,6 +284,17 @@
         }
     }
 
+    /** @return the process ID of the log, or -1. */
+    public int getProcessId() {
+        Object obj = entries.get(MetricsEvent.RESERVED_FOR_LOGBUILDER_PID);
+        if (obj instanceof Integer) {
+            return (Integer) obj;
+        } else {
+            return -1;
+        }
+    }
+
+    /** @return the name of the counter, or null. */
     public String getCounterName() {
         Object obj = entries.get(MetricsEvent.RESERVED_FOR_LOGBUILDER_NAME);
         if (obj instanceof String) {
@@ -225,6 +304,7 @@
         }
     }
 
+    /** @return the bucket label of the histogram\, or 0. */
     public long getCounterBucket() {
         Object obj = entries.get(MetricsEvent.RESERVED_FOR_LOGBUILDER_BUCKET);
         if (obj instanceof Number) {
@@ -234,11 +314,13 @@
         }
     }
 
+    /** @return true if the bucket label was specified as a long integer. */
     public boolean isLongCounterBucket() {
         Object obj = entries.get(MetricsEvent.RESERVED_FOR_LOGBUILDER_BUCKET);
         return obj instanceof Long;
     }
 
+    /** @return the increment value of the counter, or 0. */
     public int getCounterValue() {
         Object obj = entries.get(MetricsEvent.RESERVED_FOR_LOGBUILDER_VALUE);
         if (obj instanceof Integer) {
@@ -249,7 +331,7 @@
     }
 
     /**
-     * Assemble logs into structure suitable for EventLog.
+     * @return a representation of the log suitable for EventLog.
      */
     public Object[] serialize() {
         Object[] out = new Object[entries.size() * 2];
diff --git a/core/java/android/metrics/MetricsReader.java b/core/java/android/metrics/MetricsReader.java
index dd8a74d..181e87f 100644
--- a/core/java/android/metrics/MetricsReader.java
+++ b/core/java/android/metrics/MetricsReader.java
@@ -77,7 +77,8 @@
                     objects[0] = data;
                 }
                 mEventQueue.add(new LogMaker(objects)
-                        .setTimestamp(eventTimestampMs));
+                        .setTimestamp(eventTimestampMs)
+                        .setProcessId(event.getProcessId()));
                 mLastEventMs = eventTimestampMs;
             }
         }
diff --git a/core/tests/coretests/src/android/metrics/LogMakerTest.java b/core/tests/coretests/src/android/metrics/LogMakerTest.java
index ece44be..bab9f63 100644
--- a/core/tests/coretests/src/android/metrics/LogMakerTest.java
+++ b/core/tests/coretests/src/android/metrics/LogMakerTest.java
@@ -171,6 +171,14 @@
         assertEquals(null, builder.getPackageName());
     }
 
+    public void testSetAndClearPid() {
+        LogMaker builder = new LogMaker(0);
+        builder.setProcessId(1);
+        assertEquals(1, builder.getProcessId());
+        builder.clearProcessId();
+        assertEquals(-1, builder.getProcessId());
+    }
+
     public void testGiantLogOmitted() {
         LogMaker badBuilder = new LogMaker(0);
         StringBuilder b = new StringBuilder();
diff --git a/proto/src/metrics_constants.proto b/proto/src/metrics_constants.proto
index c45de0d..42446d1 100644
--- a/proto/src/metrics_constants.proto
+++ b/proto/src/metrics_constants.proto
@@ -3175,7 +3175,7 @@
     DIALOG_SUPPORT_SYSTEM_INFORMATION = 756;
 
     // These values should never appear in log outputs - they are reserved for
-    // internal Tron use.
+    // internal platform metrics use.
     RESERVED_FOR_LOGBUILDER_CATEGORY = 757;
     RESERVED_FOR_LOGBUILDER_TYPE = 758;
     RESERVED_FOR_LOGBUILDER_SUBTYPE = 759;
@@ -3282,7 +3282,7 @@
     DEFAULT_AUTOFILL_PICKER = 792;
 
     // These values should never appear in log outputs - they are reserved for
-    // internal Tron use.
+    // internal platform metrics use.
     NOTIFICATION_SINCE_CREATE_MILLIS = 793;
     NOTIFICATION_SINCE_VISIBLE_MILLIS = 794;
     NOTIFICATION_SINCE_UPDATE_MILLIS = 795;
@@ -3297,7 +3297,7 @@
     QS_NFC = 800;
 
     // These values should never appear in log outputs - they are reserved for
-    // internal Tron use.
+    // internal platform metrics use.
     RESERVED_FOR_LOGBUILDER_BUCKET = 801;
     RESERVED_FOR_LOGBUILDER_VALUE = 802;
     RESERVED_FOR_LOGBUILDER_COUNTER = 803;
@@ -3540,6 +3540,10 @@
     // OS: N
     ACTION_GET_CONTACT = 864;
 
+    // This values should never appear in log outputs - it is reserved for
+    // internal platform metrics use.
+    RESERVED_FOR_LOGBUILDER_PID = 865;
+
     // ---- End O Constants, all O constants go above this line ----
 
     // Add new aosp constants above this line.