Add MediaGpuChannelManager::LookupChannel().

media/renderers/gpu_video_accelerator_factories.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 MEDIA_RENDERERS_GPU_VIDEO_ACCELERATOR_FACTORIES_H_
 #define MEDIA_RENDERERS_GPU_VIDEO_ACCELERATOR_FACTORIES_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 55 matching lines @@
     NV12_SINGLE_GMB,  // One NV12 GMB
     NV12_DUAL_GMB,    // One R8, one RG88 GMB
   };
 
   // Return whether GPU encoding/decoding is enabled.
   virtual bool IsGpuVideoAcceleratorEnabled() = 0;
 
   // Return the channel token, or an empty token if the channel is unusable.
   virtual base::UnguessableToken GetChannelToken() = 0;
 
+  // Returns the |route_id| of the command buffer.
+  virtual int32_t GetCommandBufferRouteId() = 0;

[tguilbert, 2017/01/10 01:16:35]

Should '0' as the error value be documented?

+
   // Caller owns returned pointer, but should call Destroy() on it (instead of
   // directly deleting) for proper destruction, as per the
   // VideoDecodeAccelerator interface.
   virtual std::unique_ptr<VideoDecodeAccelerator>
   CreateVideoDecodeAccelerator() = 0;
 
   // Caller owns returned pointer, but should call Destroy() on it (instead of
   // directly deleting) for proper destruction, as per the
   // VideoEncodeAccelerator interface.
   virtual std::unique_ptr<VideoEncodeAccelerator>
@@ skipping 40 matching lines @@
       GetVideoEncodeAcceleratorSupportedProfiles() = 0;
 
  protected:
   friend class base::RefCounted<GpuVideoAcceleratorFactories>;
   virtual ~GpuVideoAcceleratorFactories() {}
 };
 
 }  // namespace media
 
 #endif  // MEDIA_RENDERERS_GPU_VIDEO_ACCELERATOR_FACTORIES_H_