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

content/browser/renderer_host/render_widget_host_view_android.h

Index: content/browser/renderer_host/render_widget_host_view_android.h
diff --git a/content/browser/renderer_host/render_widget_host_view_android.h b/content/browser/renderer_host/render_widget_host_view_android.h
index e1cf270d43dff9e83bd08433d673feb78fc76576..c51947b96b5d97a1f725e5fddd81332f821e9965 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.h
+++ b/content/browser/renderer_host/render_widget_host_view_android.h
@@ -193,11 +193,14 @@ class CONTENT_EXPORT RenderWidgetHostViewAndroid
 
   // ui::WindowAndroidObserver implementation.
   void OnCompositingDidCommit() override;
+  void OnVisibilityChanged(bool visible) override;
   void OnAttachCompositor() override;
   void OnDetachCompositor() override;
   void OnVSync(base::TimeTicks frame_time,
                base::TimeDelta vsync_period) override;
   void OnAnimate(base::TimeTicks begin_frame_time) override;
+  void OnActivityPaused() override;
+  void OnActivityResumed() override;
 
   // DelegatedFrameEvictor implementation
   void EvictDelegatedFrame() override;
@@ -290,6 +293,8 @@ class CONTENT_EXPORT RenderWidgetHostViewAndroid
       const cc::CompositorFrameMetadata& frame_metadata);
   void ComputeContentsSize(const cc::CompositorFrameMetadata& frame_metadata);
 
+  void ShowInternal();
+  void HideInternal(bool hide_frontbuffer, bool stop_observing_root_window);
   void AttachLayers();
   void RemoveLayers();