cc: Various code safety improvements in video compositing code.

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"
 #include "cc/layers/layer_impl.h"
 #include "cc/resources/release_callback_impl.h"
 #include "cc/resources/video_resource_updater.h"
 #include "media/base/video_rotation.h"
 
 namespace media {
 class VideoFrame;
 }
 
 namespace cc {
 class VideoFrameProvider;
 class VideoFrameProviderClientImpl;
 
 class CC_EXPORT VideoLayerImpl : public LayerImpl {
  public:
+  // Must be called on the impl thread while the main thread is blocked. This is
+  // so that |provider| stays alive while this is being created.
   static scoped_ptr<VideoLayerImpl> Create(LayerTreeImpl* tree_impl,
                                            int id,
                                            VideoFrameProvider* provider,
                                            media::VideoRotation video_rotation);
   ~VideoLayerImpl() override;
 
   // LayerImpl implementation.
   scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl) override;
-  void PushPropertiesTo(LayerImpl* layer) 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;
   void DidBecomeActive() override;
   void ReleaseResources() override;
 
   void SetNeedsRedraw();
-
-  void SetProviderClientImpl(
-      scoped_refptr<VideoFrameProviderClientImpl> provider_client_impl);
-
   media::VideoRotation video_rotation() const { return video_rotation_; }
 
  private:
-  VideoLayerImpl(LayerTreeImpl* tree_impl,
-                 int id,
-                 media::VideoRotation video_rotation);
+  VideoLayerImpl(
+      LayerTreeImpl* tree_impl,
+      int id,
+      scoped_refptr<VideoFrameProviderClientImpl> provider_client_impl,

[DaleCurtis, 2015/03/27 16:45:07]

I realize this is just copying existing style, but this should really be a
const& to avoid extra potential ref/unref steps (which if RefCountedThreadSafe
are atomic operations).

[danakj, 2015/03/27 16:55:15]

I guess, this happens once per video being loaded, I think that it won't matter.
A const& would be fine, or alternatively, we can swap() it into the member
variable in the constructor.

We should really get r-value reference support for scoped_refptr so we can do
this properly with a Pass() or the like.

[DaleCurtis, 2015/03/27 19:53:26]

Yeah, it's not really an issue in this case, just one of those in aggregate
style things.

+      media::VideoRotation video_rotation);
 
   const char* LayerTypeAsString() const override;
 
   scoped_refptr<VideoFrameProviderClientImpl> provider_client_impl_;
 
   scoped_refptr<media::VideoFrame> frame_;
 
   media::VideoRotation video_rotation_;
 
   scoped_ptr<VideoResourceUpdater> updater_;
   VideoFrameExternalResources::ResourceType frame_resource_type_;
   std::vector<ResourceProvider::ResourceId> frame_resources_;
 
   // TODO(danakj): Remove these, hide software path inside ResourceProvider and
   // ExternalResource (aka TextureMailbox) classes.
   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_