[Media Router] Reland: MediaRouter interfaces with stub implementations.

chrome/browser/media/router/media_router_impl.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_IMPL_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTER_IMPL_H_
+
+#include <map>
+#include <queue>
+#include <string>
+#include <vector>
+
+#include "base/callback.h"
+#include "base/containers/hash_tables.h"
+#include "base/gtest_prod_util.h"
+#include "base/macros.h"
+#include "base/memory/scoped_vector.h"
+#include "base/threading/thread_checker.h"
+#include "chrome/browser/media/router/media_router.h"
+#include "chrome/browser/media/router/media_sinks_observer.h"
+#include "components/keyed_service/core/keyed_service.h"
+
+namespace base {
+template <typename T>
+struct DefaultLazyInstanceTraits;
+}  // namespace base
+
+namespace media_router {
+
+class MediaRoute;
+class MediaRouterApiImpl;
+class MediaRoutesObserver;
+struct RoutesQueryResult;
+
+// Delegates calls to another implementation of MediaRouter, which in turn
+// handles communication with the Media Route Provider Manager (MRPM).
+// Instances of this class are created by MediaRouterImplFactory.
+// MediaRouterImpl is a profile-keyed service.
+// MediaRouterImpl runs on the browser UI thread. All observers/callbacks
+// registered to this class must also run in the UI thread.
+class MediaRouterImpl : public MediaRouter, public KeyedService {
+ public:
+  ~MediaRouterImpl() override;
+
+  // |provider_manager_host_| must be null at the time this is called.
+  // |provider_manager_host| must not be null.
+  // Does not take ownership of |provider_manager_host_|.
+  // This function can only be called once.
+  void Initialize(MediaRouter* provider_manager_host);
+
+  // MediaRouter implementation.
+  void RequestRoute(const MediaSourceId& source,
+                    const MediaSinkId& sink_id,
+                    const MediaRouteResponseCallback& callback) override;
+  void CloseRoute(const MediaRouteId& route_id) override;
+  void PostMessage(const MediaRouteId& route_id,
+                   const std::string& message) override;
+
+ private:
+  friend class MediaRouterImplFactory;
+
+  // Use MediaRouterImplFactory::GetForBrowserContext().
+  MediaRouterImpl();
+
+  // MediaRouter implementation.
+  bool RegisterMediaSinksObserver(MediaSinksObserver* observer) override;
+  void UnregisterMediaSinksObserver(MediaSinksObserver* observer) override;
+  bool RegisterMediaRoutesObserver(MediaRoutesObserver* observer) override;
+  void UnregisterMediaRoutesObserver(MediaRoutesObserver* observer) override;
+
+  // MRPM host to forward calls to MRPM to.
+  // This class does not own provider_manager_host_.
+  MediaRouter* provider_manager_host_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaRouterImpl);
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTER_IMPL_H_