[Android] Stop hiding the RWHV layer subtree when hiding the widget

ui/android/window_android.cc

Index: ui/android/window_android.cc
diff --git a/ui/android/window_android.cc b/ui/android/window_android.cc
index d8623a5cb51c93c56db979470a9c87177ab78335..9a47689295afe6df8ef074eb64a5ce72946640b9 100644
--- a/ui/android/window_android.cc
+++ b/ui/android/window_android.cc
@@ -43,6 +43,11 @@ void WindowAndroid::OnCompositingDidCommit() {
                     OnCompositingDidCommit());
 }
 
+void WindowAndroid::OnVisibilityChanged(bool visible) {
+  FOR_EACH_OBSERVER(WindowAndroidObserver, observer_list_,
+                    OnRootWindowVisibilityChanged(visible));
+}
+
 void WindowAndroid::AddObserver(WindowAndroidObserver* observer) {
   if (!observer_list_.HasObserver(observer))
     observer_list_.AddObserver(observer);
@@ -100,6 +105,14 @@ void WindowAndroid::OnVSync(JNIEnv* env,
     compositor_->OnVSync(frame_time, vsync_period);
 }
 
+void WindowAndroid::OnActivityResumed(JNIEnv* env, jobject obj) {
+  FOR_EACH_OBSERVER(WindowAndroidObserver, observer_list_, OnActivityResumed());
+}
+
+void WindowAndroid::OnActivityPaused(JNIEnv* env, jobject obj) {
+  FOR_EACH_OBSERVER(WindowAndroidObserver, observer_list_, OnActivityPaused());
+}
+
 // ----------------------------------------------------------------------------
 // Native JNI methods
 // ----------------------------------------------------------------------------