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

content/browser/renderer_host/render_widget_host_view_android.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_ANDROID_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_ANDROID_H_
 
 #include <map>
 #include <queue>
 
@@ skipping 175 matching lines @@
   void UnusedResourcesAreAvailable() override;
 
   // cc::SurfaceFactoryClient implementation.
   void ReturnResources(const cc::ReturnedResourceArray& resources) override;
 
   // ui::GestureProviderClient implementation.
   void OnGestureEvent(const ui::GestureEventData& gesture) override;
 
   // ui::WindowAndroidObserver implementation.
   void OnCompositingDidCommit() override;
+  void OnVisibilityChanged(bool visible) override;

[jdduke (slow), 2015/03/18 20:16:50]

OnVisibilityChanged is a little generic for me... what about
|OnSurfaceVisilbityChanged| or |OnWindowVisibilityChanged|?

[no sievers, 2015/03/18 21:04:48]

Maybe not 'Surface' since it's a bit overloaded already (see
'CompositingSurface' in RWH/RWHV, which means the delegated layer contents, or
'use surfaces' in here which is something different again).

OnWindowVisibilityChanged sounds good, or even OnRootWindowVisibilityChanged.

   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;
 
   SkColorType PreferredReadbackFormat() override;
 
   // StylusTextSelectorClient implementation.
   void OnStylusSelectBegin(float x0, float y0, float x1, float y1) override;
   void OnStylusSelectUpdate(float x, float y) override;
   void OnStylusSelectEnd() override;
@@ skipping 72 matching lines @@
   void SubmitFrame(scoped_ptr<cc::DelegatedFrameData> frame_data);
   void SwapDelegatedFrame(uint32 output_surface_id,
                           scoped_ptr<cc::DelegatedFrameData> frame_data);
   void SendDelegatedFrameAck(uint32 output_surface_id);
   void SendReturnedDelegatedResources(uint32 output_surface_id);
 
   void OnFrameMetadataUpdated(
       const cc::CompositorFrameMetadata& frame_metadata);
   void ComputeContentsSize(const cc::CompositorFrameMetadata& frame_metadata);
 
+  void ShowInternal();

[jdduke (slow), 2015/03/18 20:16:50]

I'll definitely add some comments here should we decide this is the approach we
want.

+  void HideInternal(bool hide_frontbuffer, bool stop_observing_root_window);
   void AttachLayers();
   void RemoveLayers();
 
   // Called after async screenshot task completes. Scales and crops the result
   // of the copy.
   static void PrepareTextureCopyOutputResult(
       const gfx::Size& dst_size_in_pixel,
       const SkColorType color_type,
       const base::TimeTicks& start_time,
       ReadbackRequestCallback& callback,
@@ skipping 125 matching lines @@
   gfx::Vector2dF last_scroll_offset_;
 
   base::WeakPtrFactory<RenderWidgetHostViewAndroid> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderWidgetHostViewAndroid);
 };
 
 } // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_WIDGET_HOST_VIEW_ANDROID_H_