[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..9e02bcc771ba74465ec7cddecb384944f527cf27 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.h
+++ b/content/browser/renderer_host/render_widget_host_view_android.h
@@ -195,9 +195,12 @@ class CONTENT_EXPORT RenderWidgetHostViewAndroid
   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;
@@ -409,6 +412,12 @@ class CONTENT_EXPORT RenderWidgetHostViewAndroid
   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);