[Media Router] Factor extension-related logic out of MediaRouterMojoImpl

chrome/browser/media/router/event_page_request_manager_factory.h

+// Copyright 2017 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_EVENT_PAGE_REQUEST_MANAGER_FACTORY_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_EVENT_PAGE_REQUEST_MANAGER_FACTORY_H_
+
+#include "base/macros.h"
+#include "base/memory/singleton.h"
+#include "components/keyed_service/content/browser_context_keyed_service_factory.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace media_router {
+
+class EventPageRequestManager;
+
+// A factory that creates EventPageRequestManager for a given BrowserContext.
+class EventPageRequestManagerFactory
+    : public BrowserContextKeyedServiceFactory {
+ public:
+  static EventPageRequestManager* GetApiForBrowserContext(
+      content::BrowserContext* context);
+
+  static EventPageRequestManagerFactory* GetInstance();
+
+ private:
+  friend struct base::DefaultSingletonTraits<EventPageRequestManagerFactory>;
+
+  EventPageRequestManagerFactory();
+  ~EventPageRequestManagerFactory() override;
+
+  KeyedService* BuildServiceInstanceFor(
+      content::BrowserContext* context) const override;
+
+  DISALLOW_COPY_AND_ASSIGN(EventPageRequestManagerFactory);
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_EVENT_PAGE_REQUEST_MANAGER_FACTORY_H_