[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 177 matching lines @@
   // 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 OnAttachCompositor() override;
   void OnDetachCompositor() override;
+  void OnVisibilityChanged(bool visible) 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 191 matching lines @@
   // Size to use if we have no backing ContentViewCore
   gfx::Size default_size_;
 
   const bool using_browser_compositor_;
 
   scoped_ptr<DelegatedFrameEvictor> frame_evictor_;
 
   size_t locks_on_frame_count_;
   bool observing_root_window_;
 
+  // If the activity is paused while the widget is visible, lock the
+  // surface. This ensures that visual content is seamlessly preserved until
+  // either window visibility is lost (e.g., when the activity is backgrounded),
+  // or the activity resumes.
+  bool should_unlock_surface_on_visibility_lost_or_activity_resumed_;
+
   struct LastFrameInfo {
     LastFrameInfo(uint32 output_id,
                   scoped_ptr<cc::CompositorFrame> output_frame);
     ~LastFrameInfo();
     uint32 output_surface_id;
     scoped_ptr<cc::CompositorFrame> frame;
   };
 
   scoped_ptr<LastFrameInfo> last_frame_info_;
 
   TextSurroundingSelectionCallback text_surrounding_selection_callback_;
 
   // List of readbackrequests waiting for arrival of a valid frame.
   std::queue<ReadbackRequest> readbacks_waiting_for_frame_;
 
   // The last scroll offset of the view.
   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_