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 7c920e2675bd04a57ed029d7d3485e9876cc798b..cb163ff817da316f5f01edc92c2c256068c07a88 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_,
-                    OnVisibilityChanged(visible));
 }
 
 void WindowAndroid::AddObserver(WindowAndroidObserver* observer) {
@@ -108,14 +103,6 @@
     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
 // ----------------------------------------------------------------------------