Revert of [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 9a47689295afe6df8ef074eb64a5ce72946640b9..d8623a5cb51c93c56db979470a9c87177ab78335 100644
--- a/ui/android/window_android.cc
+++ b/ui/android/window_android.cc
@@ -41,11 +41,6 @@
   FOR_EACH_OBSERVER(WindowAndroidObserver,
                     observer_list_,
                     OnCompositingDidCommit());
-}
-
-void WindowAndroid::OnVisibilityChanged(bool visible) {
-  FOR_EACH_OBSERVER(WindowAndroidObserver, observer_list_,
-                    OnRootWindowVisibilityChanged(visible));
 }
 
 void WindowAndroid::AddObserver(WindowAndroidObserver* observer) {
@@ -105,14 +100,6 @@
     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
 // ----------------------------------------------------------------------------