Support multiple HW video decoders per context.

content/common/gpu/gpu_channel.h

Index: content/common/gpu/gpu_channel.h
diff --git a/content/common/gpu/gpu_channel.h b/content/common/gpu/gpu_channel.h
index 5a5d501f87016a38255646a296918e454164c137..ed4a5a6719508c69b18219507ae87b06453682a1 100644
--- a/content/common/gpu/gpu_channel.h
+++ b/content/common/gpu/gpu_channel.h
@@ -122,6 +122,13 @@ class GpuChannel : public IPC::Channel::Listener,
   // TransportTexture to delete and detach itself.
   void DestroyTransportTexture(int32 route_id);
 
+  // Generate a route ID guaranteed to be unique for this channel.
+  int GenerateRouteID();
+
+  // Called to add/remove a listener for a particular message routing ID.
+  void AddRoute(int32 route_id, IPC::Channel::Listener* listener);
+  void RemoveRoute(int32 route_id);
+
  private:
   void OnDestroy();
 
@@ -129,8 +136,6 @@ class GpuChannel : public IPC::Channel::Listener,
 
   void HandleDeferredMessages();
 
-  int GenerateRouteID();
-
   // Message handlers.
   void OnInitialize(base::ProcessHandle renderer_process);
   void OnCreateOffscreenCommandBuffer(