gpu: Use mojom API for creating gpu channel.

content/common/gpu_host_messages.h

Index: content/common/gpu_host_messages.h
diff --git a/content/common/gpu_host_messages.h b/content/common/gpu_host_messages.h
index d2967dfb8d11c5508b5c0ac06dfe41c57a7f22a8..6eff4206683b85dd18b77a02ee025e5606dde106 100644
--- a/content/common/gpu_host_messages.h
+++ b/content/common/gpu_host_messages.h
@@ -55,14 +55,6 @@ IPC_STRUCT_BEGIN(GpuMsg_CreateGpuMemoryBuffer_Params)
   IPC_STRUCT_MEMBER(gpu::SurfaceHandle, surface_handle)
 IPC_STRUCT_END()
 
-IPC_STRUCT_TRAITS_BEGIN(content::EstablishChannelParams)
-  IPC_STRUCT_TRAITS_MEMBER(client_id)
-  IPC_STRUCT_TRAITS_MEMBER(client_tracing_id)
-  IPC_STRUCT_TRAITS_MEMBER(preempts)
-  IPC_STRUCT_TRAITS_MEMBER(allow_view_command_buffers)
-  IPC_STRUCT_TRAITS_MEMBER(allow_real_time_streams)
-IPC_STRUCT_TRAITS_END()
-
 IPC_STRUCT_TRAITS_BEGIN(gpu::GpuPreferences)
   IPC_STRUCT_TRAITS_MEMBER(single_process)
   IPC_STRUCT_TRAITS_MEMBER(in_process_gpu)
@@ -110,15 +102,6 @@ IPC_STRUCT_TRAITS_END()
 // Tells the GPU process to shutdown itself.
 IPC_MESSAGE_CONTROL0(GpuMsg_Finalize)
 
-// Tells the GPU process to create a new channel for communication with a
-// given client.  The channel name is returned in a
-// GpuHostMsg_ChannelEstablished message.  The client ID is passed so
-// that the GPU process reuses an existing channel to that process if it exists.
-// This ID is a unique opaque identifier generated by the browser process.
-// The client_tracing_id is a unique ID used for the purposes of tracing.
-IPC_MESSAGE_CONTROL1(GpuMsg_EstablishChannel,
-                     content::EstablishChannelParams /* params */)
-
 // Tells the GPU process to close the channel identified by |client_id|.
 // If no channel can be identified, do nothing.
 IPC_MESSAGE_CONTROL1(GpuMsg_CloseChannel, int32_t /* client_id */)
@@ -175,10 +158,6 @@ IPC_MESSAGE_CONTROL3(GpuHostMsg_Initialized,
                      ::gpu::GPUInfo /* gpu_info */,
                      ::gpu::GpuFeatureInfo /* gpu_feature_info */)
 
-// Response from GPU to a GpuHostMsg_EstablishChannel message.
-IPC_MESSAGE_CONTROL1(GpuHostMsg_ChannelEstablished,
-                     IPC::ChannelHandle /* channel_handle */)
-
 // Message to the GPU that a shader was loaded from disk.
 IPC_MESSAGE_CONTROL1(GpuMsg_LoadedShader, std::string /* encoded shader */)