cc: Video layers without a frame should not occlude

cc/layers/video_layer_impl.h

 // Copyright 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 CC_LAYERS_VIDEO_LAYER_IMPL_H_
 #define CC_LAYERS_VIDEO_LAYER_IMPL_H_
 
 #include <vector>
 
 #include "cc/base/cc_export.h"
@@ skipping 20 matching lines @@
                                            media::VideoRotation video_rotation);
   ~VideoLayerImpl() override;
 
   // LayerImpl implementation.
   scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl) override;
   bool WillDraw(DrawMode draw_mode,
                 ResourceProvider* resource_provider) override;
   void AppendQuads(RenderPass* render_pass,
                    AppendQuadsData* append_quads_data) override;
   void DidDraw(ResourceProvider* resource_provider) override;
+  SimpleEnclosedRegion VisibleContentOpaqueRegion() const override;
   void DidBecomeActive() override;
   void ReleaseResources() override;
 
   void SetNeedsRedraw();
   media::VideoRotation video_rotation() const { return video_rotation_; }
 
  private:
   VideoLayerImpl(
       LayerTreeImpl* tree_impl,
       int id,
@@ skipping 17 matching lines @@
   std::vector<unsigned> software_resources_;
   // Called once for each software resource.
   ReleaseCallbackImpl software_release_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoLayerImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_VIDEO_LAYER_IMPL_H_