[Media Router] Design MediaRouter interface with stub implementation.

chrome/browser/media/router/media_router.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_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTER_H_
+
+#include <string>
+#include <vector>
+
+#include "chrome/browser/media/router/media_route_id.h"
+#include "chrome/browser/media/router/media_sink.h"
+
+namespace media_router {
+
+class MediaRoute;
+class MediaRouteResponse;
+class MediaRoutesObserver;
+class MediaSource;
+class MediaSinksObserver;
+
+using MediaRouteResponseCallback =
+    base::Callback<void(const MediaRouteResponse&)>;
+
+// An interface for handling resources related to media routing.
+// Responsible for registering observers for receiving sink availability updates
+// as well as handling route requests/responses.
+class MediaRouter {
+ public:
+  virtual ~MediaRouter();
+
+  // Requests a media route from |source| to |sink_id|.
+  // |callback| is invoked with a response indicating success or failure.
+  virtual RouteRequestId StartRouteRequest(
+      const MediaSource& source,
+      const MediaSinkId& sink_id,
+      const MediaRouteResponseCallback& callback) = 0;
+
+  // Unregisters a pending media route request, e.g. when the MR UI is closed.
+  virtual void UnregisterMediaRouteResponseCallback(
+      const RouteRequestId& request_id) = 0;
+
+  // Closes a media route specified by |route_id|.
+  virtual void CloseRoute(const MediaRouteId& route_id) = 0;
+
+  // Registers |observer| with MediaRouter so that it will receive updates on
+  // sinks that are compatible with the source specified in it.
+  // Initial set of updates may be returned synchronously to |observer|.
+  // NOTE: This class does not assume ownership of |observer|. Callers must
+  // manage |observer| and make sure |UnregisterObserver()| is called
+  // before the observer is destroyed.
+  // Returns true if registration succeeded or the |observer| already exists.
+  // If the MRPM Host is not available, the registration request will fail
+  // immediately.
+  virtual bool RegisterObserver(MediaSinksObserver* observer) = 0;
+
+  // Unregisters |observer| from MediaRouter.
+  virtual void UnregisterObserver(MediaSinksObserver* observer) = 0;
+
+  // Posts |message| with optional |extra_info_json| to a MediaSink connected
+  // via MediaRoute with |route_id|.
+  virtual void PostMessage(const MediaRouteId& route_id,
+                           const std::string& message,
+                           const std::string& extra_info_json) = 0;
+
+  // Adds a MediaRoutesObserver to listen for updates on MediaRoutes.
+  // MediaRouter does not own |observer|. |RemoveMediaRoutesObserver| should
+  // be called before |observer| is destroyed.
+  virtual void AddMediaRoutesObserver(MediaRoutesObserver* observer) = 0;
+
+  // Removes a previously added MediaRoutesObserver. |observer| will stop
+  // receiving updates from MediaRouter.
+  virtual void RemoveMediaRoutesObserver(MediaRoutesObserver* observer) = 0;
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTER_H_