Merge "Avoid sending messages of destroyed Engine" into udc-dev am: 359c0a200f am: 3b1013b1ab

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24103711

Change-Id: Ie7dc8202a6ef3583bc744decdad35c49d41908d1
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

core/java/android/service/wallpaper/WallpaperService.java

@@ -868,6 +868,11 @@ public abstract class WallpaperService extends Service {
          * This will trigger a {@link #onComputeColors()} call.
          */
         public void notifyColorsChanged() {
+            if (mDestroyed) {
+                Log.i(TAG, "Ignoring notifyColorsChanged(), Engine has already been destroyed.");
+                return;
+            }
+
             final long now = mClockFunction.get();
             if (now - mLastColorInvalidation < NOTIFY_COLORS_RATE_LIMIT_MS) {
                 Log.w(TAG, "This call has been deferred. You should only call "
@@ -2226,7 +2231,11 @@ public abstract class WallpaperService extends Service {
             }
         }
 
-        void detach() {
+        /**
+         * @hide
+         */
+        @VisibleForTesting
+        public void detach() {
             if (mDestroyed) {
                 return;
             }
@@ -2442,6 +2451,14 @@ public abstract class WallpaperService extends Service {
         }
 
         public void reportShown() {
+            if (mEngine == null) {
+                Log.i(TAG, "Can't report null engine as shown.");
+                return;
+            }
+            if (mEngine.mDestroyed) {
+                Log.i(TAG, "Engine was destroyed before we could draw.");
+                return;
+            }
             if (!mShownReported) {
                 mShownReported = true;
                 Trace.beginSection("WPMS.mConnection.engineShown");

tests/Internal/src/android/service/wallpaper/OWNERS

@@ -0,0 +1,4 @@
+dupin@google.com
+santie@google.com
+pomini@google.com
+poultney@google.com

tests/Internal/src/android/service/wallpaper/WallpaperServiceTest.java

@@ -85,4 +85,17 @@ public class WallpaperServiceTest {
         assertEquals("onAmbientModeChanged should have been called", 2, zoomChangedCount[0]);
     }
 
+    @Test
+    public void testNotifyColorsOfDestroyedEngine_doesntCrash() {
+        WallpaperService service = new WallpaperService() {
+            @Override
+            public Engine onCreateEngine() {
+                return new Engine();
+            }
+        };
+        WallpaperService.Engine engine = service.onCreateEngine();
+        engine.detach();
+
+        engine.notifyColorsChanged();
+    }
 }