Add embedder api for participating in gpu logic

content/public/browser/gpu_service_registry.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 CONTENT_PUBLIC_BROWSER_GPU_SERVICE_REGISTRY_H_
+#define CONTENT_PUBLIC_BROWSER_GPU_SERVICE_REGISTRY_H_
+
+#include "content/common/content_export.h"
+
+namespace content {
+class ServiceRegistry;
+
+// Get ServiceRegistry registered via ContentGpuClient::RegisterMojoServices().
+// This must be called on IO thread.
+CONTENT_EXPORT ServiceRegistry* GetGpuServiceRegistry();
+
+}  // namespace content
+
+#endif  // CONTENT_PUBLIC_BROWSER_GPU_SERVICE_REGISTRY_H_