Remove activity from stopping activities once resumed.

Previously we were waiting for the activity to become visible before
removing from this list. This can lead to a race condition where the
activity is resumed and the stopping activities are cleaned up. If
the activity has not become visible, the resumed activity will be
stopped.

This CL addresses the issue by removing the activity from the
stopping activities list once resume has completed.

Change-Id: Ic33906327e538920961e60064a6ae976864509be
Fixes: 63804822
Test: bit FrameworksServicesTests:com.android.server.am.ActivityStackSupervisorTests#testStoppingActivityRemovedWhenResumed

services/core/java/com/android/server/am/ActivityStackSupervisor.java

@@ -3297,6 +3297,9 @@ public class ActivityStackSupervisor extends ConfigurationContainer implements D
     }
 
     boolean reportResumedActivityLocked(ActivityRecord r) {
+        // A resumed activity cannot be stopping. remove from list
+        mStoppingActivities.remove(r);
+
         final ActivityStack stack = r.getStack();
         if (isFocusedStack(stack)) {
             mService.updateUsageStats(r, true);

services/tests/servicestests/src/com/android/server/am/ActivityStackSupervisorTests.java

@@ -21,6 +21,7 @@ import static android.app.ActivityManager.StackId.PINNED_STACK_ID;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertFalse;
 
 import android.content.ComponentName;
 import android.graphics.Rect;
@@ -117,4 +118,21 @@ public class ActivityStackSupervisorTests extends ActivityTestsBase {
             assertTrue(stackTasks.contains(task));
         }
     }
+
+    /**
+     * Ensures that an activity is removed from the stopping activities list once it is resumed.
+     */
+    @Test
+    public void testStoppingActivityRemovedWhenResumed() throws Exception {
+        final ActivityManagerService service = createActivityManagerService();
+        final TaskRecord firstTask = createTask(service, testActivityComponent,
+            FULLSCREEN_WORKSPACE_STACK_ID);
+        final ActivityRecord firstActivity = createActivity(service, testActivityComponent,
+            firstTask);
+        service.mStackSupervisor.mStoppingActivities.add(firstActivity);
+
+        firstActivity.completeResumeLocked();
+
+        assertFalse(service.mStackSupervisor.mStoppingActivities.contains(firstActivity));
+    }
 }

services/tests/servicestests/src/com/android/server/am/ActivityTestsBase.java

@@ -145,6 +145,10 @@ public class ActivityTestsBase {
         protected ActivityStackSupervisor createStackSupervisor() {
             return new TestActivityStackSupervisor(this, mHandlerThread.getLooper());
         }
+
+        @Override
+        void updateUsageStats(ActivityRecord component, boolean resumed) {
+        }
     }
 
     /**