services/ui: Detect when a video is playing

cc/layers/layer_impl.h

Index: cc/layers/layer_impl.h
diff --git a/cc/layers/layer_impl.h b/cc/layers/layer_impl.h
index a3c621dd3577e7b350fb0880afd864e84ba66895..a3b8a32e96110ec0dc4831417e9f6fc14d6f56d8 100644
--- a/cc/layers/layer_impl.h
+++ b/cc/layers/layer_impl.h
@@ -425,6 +425,9 @@ class CC_EXPORT LayerImpl {
     return is_drawn_render_surface_layer_list_member_;
   }
 
+  void set_may_contain_video(bool yes) { may_contain_video_ = yes; }
+  bool may_contain_video() const { return may_contain_video_; }
+
   void Set3dSortingContextId(int id);
   int sorting_context_id() { return sorting_context_id_; }
 
@@ -522,6 +525,7 @@ class CC_EXPORT LayerImpl {
 
   // Tracks if drawing-related properties have changed since last redraw.
   bool layer_property_changed_ : 1;
+  bool may_contain_video_ : 1;
 
   bool masks_to_bounds_ : 1;
   bool contents_opaque_ : 1;