Fireperf: fix screen trace in multi-activity apps (#3311)

* mstop screen trace in onPause

* onActivityPostPaused

* fix test

* fix test typo

* add debug message

Author: leotianlizhan

firebase-perf/src/main/java/com/google/firebase/perf/application/AppStateMonitor.java

@@ -163,10 +163,6 @@ public synchronized void onActivityStarted(Activity activity) {
 
   @Override
   public synchronized void onActivityStopped(Activity activity) {
-    if (isScreenTraceSupported(activity)) {
-      sendScreenTrace(activity);
-    }
-
     // Last activity has its onActivityStopped called, the app goes to background.
     if (activityToResumedMap.containsKey(activity)) {
       activityToResumedMap.remove(activity);
@@ -295,6 +291,14 @@ public void onActivitySaveInstanceState(Activity activity, Bundle outState) {}
   @Override
   public void onActivityPaused(Activity activity) {}
 
+  /** Stops screen trace right after onPause because of b/210055697 */
+  @Override
+  public void onActivityPostPaused(@NonNull Activity activity) {
+    if (isScreenTraceSupported(activity)) {
+      sendScreenTrace(activity);
+    }
+  }
+
   /**
    * Send screen trace. If hardware acceleration is not enabled, all frame metrics will be zero and
    * the trace will not be sent.
@@ -321,6 +325,11 @@ private void sendScreenTrace(Activity activity) {
      * FrameMetricsAggregator#remove(Activity)} will throw exceptions for hardware acceleration
      * disabled activities.
      */
+    try {
+      frameMetricsAggregator.remove(activity);
+    } catch (IllegalArgumentException ignored) {
+      logger.debug("View not hardware accelerated. Unable to collect screen trace.");
+    }
     SparseIntArray[] arr = frameMetricsAggregator.reset();
     if (arr != null) {
       SparseIntArray frameTimes = arr[FrameMetricsAggregator.TOTAL_INDEX];

firebase-perf/src/test/java/com/google/firebase/perf/application/AppStateMonitorTest.java

@@ -369,7 +369,7 @@ public void screenTrace_twoActivities_traceStartedAndStoppedWithActivityLifecycl
       monitor.onActivityStarted(activity);
       assertThat(monitor.getActivity2ScreenTrace()).hasSize(1);
       currentTime = endTime;
-      monitor.onActivityStopped(activity);
+      monitor.onActivityPostPaused(activity);
       Assert.assertEquals(0, monitor.getActivity2ScreenTrace().size());
     }
   }
@@ -421,7 +421,7 @@ public void screenTrace_perfMonEnabledSwitchAtRuntime_traceCreationDependsOnRunt
     monitor.onActivityStarted(activityWithNonHardwareAcceleratedView);
     assertThat(monitor.getActivity2ScreenTrace()).hasSize(1);
     currentTime = 200;
-    monitor.onActivityStopped(activityWithNonHardwareAcceleratedView);
+    monitor.onActivityPostPaused(activityWithNonHardwareAcceleratedView);
     assertThat(monitor.getActivity2ScreenTrace()).isEmpty();
 
     // Case #2: developer has disabled Performance Monitoring during runtime.
@@ -431,7 +431,7 @@ public void screenTrace_perfMonEnabledSwitchAtRuntime_traceCreationDependsOnRunt
     monitor.onActivityStarted(activityWithNonHardwareAcceleratedView);
     assertThat(monitor.getActivity2ScreenTrace()).isEmpty();
     // Confirm that this doesn't throw an exception.
-    monitor.onActivityStopped(activityWithNonHardwareAcceleratedView);
+    monitor.onActivityPostPaused(activityWithNonHardwareAcceleratedView);
   }
 
   @Test