cc: Video layers without a frame should not occlude

cc/layers/video_frame_provider_client_impl.h

 // Copyright 2013 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_FRAME_PROVIDER_CLIENT_IMPL_H_
 #define CC_LAYERS_VIDEO_FRAME_PROVIDER_CLIENT_IMPL_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "base/threading/thread_checker.h"
@@ skipping 24 matching lines @@
   VideoLayerImpl* ActiveVideoLayer() const;
   void SetActiveVideoLayer(VideoLayerImpl* video_layer);
 
   bool Stopped() const;
   // Must be called on the impl thread while the main thread is blocked.
   void Stop();
 
   scoped_refptr<media::VideoFrame> AcquireLockAndCurrentFrame();
   void PutCurrentFrame();
   void ReleaseLock();
+  bool HasCurrentFrame();
 
   const gfx::Transform& StreamTextureMatrix() const;
 
   // VideoFrameController implementation.
   void OnBeginFrame(const BeginFrameArgs& args) override;
 
   // VideoFrameProvider::Client implementation.
   // Called on the main thread.
   void StopUsingProvider() override;
   // Called on the impl thread.
@@ skipping 23 matching lines @@
   base::ThreadChecker thread_checker_;
 
   gfx::Transform stream_texture_matrix_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoFrameProviderClientImpl);
 };
 
 }  // namespace cc
 
 #endif  // CC_LAYERS_VIDEO_FRAME_PROVIDER_CLIENT_IMPL_H_