Dismiss recents when device goes to sleep

Dismiss recents automatically after lock and unlock the device, otherwise recents screen becomes non-responsive for 3P Launchers.

Bug: 319365581
Change-Id: I6571f25cf311ca586f6d9c9e1228f1addcbed1f1
Flag: EXEMPT bugfix.
Test: FallbackRecentsTest

quickstep/src/com/android/quickstep/RecentsActivity.java

@@ -361,6 +361,14 @@ public final class RecentsActivity extends StatefulActivity<RecentsState> implem
                 this, LAUNCHER_ACTIVITY_STOPPED_MESSAGE);
     }
 
+    @Override
+    public void onUiChangedWhileSleeping() {
+        super.onUiChangedWhileSleeping();
+        // Dismiss recents and navigate to home if the device goes to sleep
+        // while in recents.
+        startHome();
+    }
+
     @Override
     protected void onResume() {
         super.onResume();