Adds identifier to TaskSnapshot

This identifier is introduced to differentiate two task snapshots in
AiAi. Currently, the timestamp (in millis) is chosen as the identifier.

Bug: 136563752
Test: atest TaskSnapshotPersisterLoaderTest
Change-Id: I249511d1e4bb34a93d5db08d2b1cea3b1ee5d034
diff --git a/core/java/android/app/ActivityManager.java b/core/java/android/app/ActivityManager.java
index 17368b7..5dbb970 100644
--- a/core/java/android/app/ActivityManager.java
+++ b/core/java/android/app/ActivityManager.java
@@ -1822,7 +1822,8 @@
      * @hide
      */
     public static class TaskSnapshot implements Parcelable {
-
+        // Identifier of this snapshot
+        private final long mId;
         // Top activity in task when snapshot was taken
         private final ComponentName mTopActivityComponent;
         private final GraphicBuffer mSnapshot;
@@ -1841,10 +1842,12 @@
         // Must be one of the named color spaces, otherwise, always use SRGB color space.
         private final ColorSpace mColorSpace;
 
-        public TaskSnapshot(@NonNull ComponentName topActivityComponent, GraphicBuffer snapshot,
+        public TaskSnapshot(long id,
+                @NonNull ComponentName topActivityComponent, GraphicBuffer snapshot,
                 @NonNull ColorSpace colorSpace, int orientation, Rect contentInsets,
                 boolean reducedResolution, float scale, boolean isRealSnapshot, int windowingMode,
                 int systemUiVisibility, boolean isTranslucent) {
+            mId = id;
             mTopActivityComponent = topActivityComponent;
             mSnapshot = snapshot;
             mColorSpace = colorSpace.getId() < 0
@@ -1860,6 +1863,7 @@
         }
 
         private TaskSnapshot(Parcel source) {
+            mId = source.readLong();
             mTopActivityComponent = ComponentName.readFromParcel(source);
             mSnapshot = source.readParcelable(null /* classLoader */);
             int colorSpaceId = source.readInt();
@@ -1877,6 +1881,13 @@
         }
 
         /**
+         * @return Identifier of this snapshot.
+         */
+        public long getId() {
+            return mId;
+        }
+
+        /**
          * @return The top activity component for the task at the point this snapshot was taken.
          */
         public ComponentName getTopActivityComponent() {
@@ -1970,6 +1981,7 @@
 
         @Override
         public void writeToParcel(Parcel dest, int flags) {
+            dest.writeLong(mId);
             ComponentName.writeToParcel(mTopActivityComponent, dest);
             dest.writeParcelable(mSnapshot, 0);
             dest.writeInt(mColorSpace.getId());
@@ -1988,6 +2000,7 @@
             final int width = mSnapshot != null ? mSnapshot.getWidth() : 0;
             final int height = mSnapshot != null ? mSnapshot.getHeight() : 0;
             return "TaskSnapshot{"
+                    + " mId=" + mId
                     + " mTopActivityComponent=" + mTopActivityComponent.flattenToShortString()
                     + " mSnapshot=" + mSnapshot + " (" + width + "x" + height + ")"
                     + " mColorSpace=" + mColorSpace.toString()
diff --git a/packages/SystemUI/shared/src/com/android/systemui/shared/recents/model/ThumbnailData.java b/packages/SystemUI/shared/src/com/android/systemui/shared/recents/model/ThumbnailData.java
index 98a8110..98b7e24 100644
--- a/packages/SystemUI/shared/src/com/android/systemui/shared/recents/model/ThumbnailData.java
+++ b/packages/SystemUI/shared/src/com/android/systemui/shared/recents/model/ThumbnailData.java
@@ -38,6 +38,7 @@
     public int windowingMode;
     public int systemUiVisibility;
     public float scale;
+    public long snapshotId;
 
     public ThumbnailData() {
         thumbnail = null;
@@ -49,6 +50,7 @@
         isTranslucent = false;
         windowingMode = WINDOWING_MODE_UNDEFINED;
         systemUiVisibility = 0;
+        snapshotId = 0;
     }
 
     public ThumbnailData(TaskSnapshot snapshot) {
@@ -61,5 +63,6 @@
         isTranslucent = snapshot.isTranslucent();
         windowingMode = snapshot.getWindowingMode();
         systemUiVisibility = snapshot.getSystemUiVisibility();
+        snapshotId = snapshot.getId();
     }
 }
diff --git a/proto/src/task_snapshot.proto b/proto/src/task_snapshot.proto
index 381d983..821db86 100644
--- a/proto/src/task_snapshot.proto
+++ b/proto/src/task_snapshot.proto
@@ -33,4 +33,5 @@
      bool is_translucent = 9;
      string top_activity_component = 10;
      float scale = 11;
- }
\ No newline at end of file
+     int64 id = 12;
+ }
diff --git a/services/core/java/com/android/server/wm/TaskSnapshotController.java b/services/core/java/com/android/server/wm/TaskSnapshotController.java
index bd114d9..f9a6fe7 100644
--- a/services/core/java/com/android/server/wm/TaskSnapshotController.java
+++ b/services/core/java/com/android/server/wm/TaskSnapshotController.java
@@ -310,6 +310,7 @@
         }
         final boolean isWindowTranslucent = mainWindow.getAttrs().format != PixelFormat.OPAQUE;
         return new TaskSnapshot(
+                System.currentTimeMillis() /* id */,
                 appWindowToken.mActivityComponent, screenshotBuffer.getGraphicBuffer(),
                 screenshotBuffer.getColorSpace(),
                 appWindowToken.getTask().getConfiguration().orientation,
@@ -404,7 +405,9 @@
 
         // Note, the app theme snapshot is never translucent because we enforce a non-translucent
         // color above
-        return new TaskSnapshot(topChild.mActivityComponent, hwBitmap.createGraphicBufferHandle(),
+        return new TaskSnapshot(
+                System.currentTimeMillis() /* id */,
+                topChild.mActivityComponent, hwBitmap.createGraphicBufferHandle(),
                 hwBitmap.getColorSpace(), topChild.getTask().getConfiguration().orientation,
                 getInsets(mainWindow), ActivityManager.isLowRamDeviceStatic() /* reduced */,
                 mFullSnapshotScale, false /* isRealSnapshot */, task.getWindowingMode(),
diff --git a/services/core/java/com/android/server/wm/TaskSnapshotLoader.java b/services/core/java/com/android/server/wm/TaskSnapshotLoader.java
index fcd97c1..696e1c3 100644
--- a/services/core/java/com/android/server/wm/TaskSnapshotLoader.java
+++ b/services/core/java/com/android/server/wm/TaskSnapshotLoader.java
@@ -92,7 +92,7 @@
             // For legacy snapshots, restore the scale based on the reduced resolution state
             final float legacyScale = reducedResolution ? mPersister.getReducedScale() : 1f;
             final float scale = Float.compare(proto.scale, 0f) != 0 ? proto.scale : legacyScale;
-            return new TaskSnapshot(topActivityComponent, buffer, bitmap.getColorSpace(),
+            return new TaskSnapshot(proto.id, topActivityComponent, buffer, bitmap.getColorSpace(),
                     proto.orientation,
                     new Rect(proto.insetLeft, proto.insetTop, proto.insetRight, proto.insetBottom),
                     reducedResolution, scale, proto.isRealSnapshot, proto.windowingMode,
diff --git a/services/core/java/com/android/server/wm/TaskSnapshotPersister.java b/services/core/java/com/android/server/wm/TaskSnapshotPersister.java
index 72fc189..32a1d90 100644
--- a/services/core/java/com/android/server/wm/TaskSnapshotPersister.java
+++ b/services/core/java/com/android/server/wm/TaskSnapshotPersister.java
@@ -343,6 +343,7 @@
             proto.isTranslucent = mSnapshot.isTranslucent();
             proto.topActivityComponent = mSnapshot.getTopActivityComponent().flattenToString();
             proto.scale = mSnapshot.getScale();
+            proto.id = mSnapshot.getId();
             final byte[] bytes = TaskSnapshotProto.toByteArray(proto);
             final File file = getProtoFile(mTaskId, mUserId);
             final AtomicFile atomicFile = new AtomicFile(file);
diff --git a/services/tests/wmtests/src/com/android/server/wm/TaskSnapshotPersisterLoaderTest.java b/services/tests/wmtests/src/com/android/server/wm/TaskSnapshotPersisterLoaderTest.java
index f958867..b29453a 100644
--- a/services/tests/wmtests/src/com/android/server/wm/TaskSnapshotPersisterLoaderTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/TaskSnapshotPersisterLoaderTest.java
@@ -64,6 +64,7 @@
         assertTrueForFiles(files, File::exists, " must exist");
         final TaskSnapshot snapshot = mLoader.loadTask(1, mTestUserId, false /* reduced */);
         assertNotNull(snapshot);
+        assertEquals(MOCK_SNAPSHOT_ID, snapshot.getId());
         assertEquals(TEST_INSETS, snapshot.getContentInsets());
         assertNotNull(snapshot.getSnapshot());
         assertEquals(Configuration.ORIENTATION_PORTRAIT, snapshot.getOrientation());
diff --git a/services/tests/wmtests/src/com/android/server/wm/TaskSnapshotPersisterTestBase.java b/services/tests/wmtests/src/com/android/server/wm/TaskSnapshotPersisterTestBase.java
index e004cd3..f749622 100644
--- a/services/tests/wmtests/src/com/android/server/wm/TaskSnapshotPersisterTestBase.java
+++ b/services/tests/wmtests/src/com/android/server/wm/TaskSnapshotPersisterTestBase.java
@@ -45,6 +45,7 @@
 
     private static final Rect TEST_INSETS = new Rect(10, 20, 30, 40);
     static final File FILES_DIR = getInstrumentation().getTargetContext().getFilesDir();
+    static final long MOCK_SNAPSHOT_ID = 12345678;
 
     TaskSnapshotPersister mPersister;
     TaskSnapshotLoader mLoader;
@@ -129,7 +130,7 @@
             Canvas c = buffer.lockCanvas();
             c.drawColor(Color.RED);
             buffer.unlockCanvasAndPost(c);
-            return new TaskSnapshot(new ComponentName("", ""), buffer,
+            return new TaskSnapshot(MOCK_SNAPSHOT_ID, new ComponentName("", ""), buffer,
                     ColorSpace.get(ColorSpace.Named.SRGB), ORIENTATION_PORTRAIT, TEST_INSETS,
                     mReducedResolution, mScale, mIsRealSnapshot,
                     mWindowingMode, mSystemUiVisibility, mIsTranslucent);
diff --git a/services/tests/wmtests/src/com/android/server/wm/TaskSnapshotSurfaceTest.java b/services/tests/wmtests/src/com/android/server/wm/TaskSnapshotSurfaceTest.java
index 4ca01ec..74db820 100644
--- a/services/tests/wmtests/src/com/android/server/wm/TaskSnapshotSurfaceTest.java
+++ b/services/tests/wmtests/src/com/android/server/wm/TaskSnapshotSurfaceTest.java
@@ -64,7 +64,9 @@
             int windowFlags, Rect taskBounds) {
         final GraphicBuffer buffer = GraphicBuffer.create(width, height, PixelFormat.RGBA_8888,
                 GraphicBuffer.USAGE_SW_READ_RARELY | GraphicBuffer.USAGE_SW_WRITE_NEVER);
-        final TaskSnapshot snapshot = new TaskSnapshot(new ComponentName("", ""), buffer,
+        final TaskSnapshot snapshot = new TaskSnapshot(
+                System.currentTimeMillis(),
+                new ComponentName("", ""), buffer,
                 ColorSpace.get(ColorSpace.Named.SRGB), ORIENTATION_PORTRAIT, contentInsets, false,
                 1.0f, true /* isRealSnapshot */, WINDOWING_MODE_FULLSCREEN,
                 0 /* systemUiVisibility */, false /* isTranslucent */);