[Media Router] Add Media Router Mojo impl code.

chrome/browser/media/router/media_router_mojo_impl_factory.h

+// Copyright 2015 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 CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTER_MOJO_IMPL_FACTORY_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTER_MOJO_IMPL_FACTORY_H_
+
+#include "base/lazy_instance.h"
+#include "components/keyed_service/content/browser_context_keyed_service_factory.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace media_router {
+
+class MediaRouterMojoImpl;
+
+// A factory that lazily returns a MediaRouterMojoImpl object for a given
+// BrowserContext.
+class MediaRouterMojoImplFactory : public BrowserContextKeyedServiceFactory {
+ public:
+  static MediaRouterMojoImpl* GetApiForBrowserContext(
+      content::BrowserContext* context);
+
+ private:
+  friend struct base::DefaultLazyInstanceTraits<MediaRouterMojoImplFactory>;
+
+  MediaRouterMojoImplFactory();
+  ~MediaRouterMojoImplFactory() override;
+
+  // BrowserContextKeyedServiceFactory interface.
+  KeyedService* BuildServiceInstanceFor(
+      content::BrowserContext* context) const override;
+  content::BrowserContext* GetBrowserContextToUse(
+      content::BrowserContext* context) const override;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaRouterMojoImplFactory);
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTER_MOJO_IMPL_FACTORY_H_