Establish mojo service between Canvas (blink) and SurfaceManager (browser)

cc/ipc/surface_id_struct_traits.h

 // Copyright 2016 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_IPC_SURFACE_ID_STRUCT_TRAITS_H_
 #define CC_IPC_SURFACE_ID_STRUCT_TRAITS_H_
 
-#include "cc/ipc/surface_id.mojom.h"
 #include "cc/surfaces/surface_id.h"
 
 namespace mojo {
 
-template <>
-struct StructTraits<cc::mojom::SurfaceId, cc::SurfaceId> {
+// This template is fully specialized as cc::mojom::SurfaceId and
+// as cc::mojom::blink::SurfaceId, in generated .mojom.h and .mojom-blink.h
+// respectively.
+template <typename T>
+struct StructTraits<T, cc::SurfaceId> {
   static uint32_t id_namespace(const cc::SurfaceId& id) {
     return id.id_namespace();
   }
 
   static uint32_t local_id(const cc::SurfaceId& id) { return id.local_id(); }
 
   static uint64_t nonce(const cc::SurfaceId& id) { return id.nonce(); }
 
-  static bool Read(cc::mojom::SurfaceIdDataView data, cc::SurfaceId* out) {
+  static bool Read(typename T::DataView data, cc::SurfaceId* out) {
     *out = cc::SurfaceId(data.id_namespace(), data.local_id(), data.nonce());
     return true;
   }
 };
 
 }  // namespace mojo
 
 #endif  // CC_IPC_SURFACE_ID_STRUCT_TRAITS_H_