Add/remove surface references via MojoCompositorFrameSink.

cc/ipc/surface_reference_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_REFERENCE_STRUCT_TRAITS_H_
+#define CC_IPC_SURFACE_REFERENCE_STRUCT_TRAITS_H_
+
+#include "cc/ipc/surface_id_struct_traits.h"
+#include "cc/ipc/surface_reference.mojom-shared.h"
+#include "cc/surfaces/surface_id.h"
+#include "cc/surfaces/surface_reference.h"
+
+namespace mojo {
+
+template <>
+struct StructTraits<cc::mojom::SurfaceReferenceDataView, cc::SurfaceReference> {
+  static const cc::SurfaceId& parent_id(const cc::SurfaceReference& ref) {
+    return ref.parent_id();
+  }
+
+  static const cc::SurfaceId& child_id(const cc::SurfaceReference& ref) {
+    return ref.child_id();
+  }
+
+  static bool Read(cc::mojom::SurfaceReferenceDataView data,
+                   cc::SurfaceReference* out) {
+    if (!data.ReadChildId(&out->child_id_))
+      return false;
+
+    if (!data.ReadParentId(&out->parent_id_))
+      return false;
+
+    return true;
+  }
+};
+
+}  // namespace mojo
+
+#endif  // CC_IPC_SURFACE_REFERENCE_STRUCT_TRAITS_H_