[Media Router] Design MediaRouter interface with stub implementation.

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_route_provider_manager_host.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;
+
+// Implementation of MediaRouter that delegates calls to
+// MediaRouteProviderManagerHost, which in turn handles communication
+// with the Media Route Provider Manager (MRPM).
+// In addition, responses from MediaRouteProviderManagerHost are delegated to
+// this class which then invokes the observers / callbacks.
+// 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 MediaRouteProviderManagerHost::Delegate {
+ public:
+  ~MediaRouterImpl() override;
+
+  // |mrpm_host_| must be null at the time this is called.
+  // |mrpm_host| must not be null.
+  // Does not take ownership of |mrpm_host_|.
+  // This function can only be called once.
+  void Initialize(MediaRouteProviderManagerHost* mrpm_host);
+
+  // MediaRouter implementation.
+  RouteRequestId StartRouteRequest(
+      const MediaSource& source,
+      const MediaSinkId& sink_id,
+      const MediaRouteResponseCallback& callback) override;
+  void UnregisterMediaRouteResponseCallback(
+      const RouteRequestId& request_id) override;
+  void CloseRoute(const MediaRouteId& route_id) override;
+  bool RegisterMediaSinksObserver(MediaSinksObserver* observer) override;
+  void UnregisterMediaSinksObserver(MediaSinksObserver* observer) override;
+  void PostMessage(const MediaRouteId& route_id,
+                   const std::string& message) override;
+  bool RegisterMediaRoutesObserver(MediaRoutesObserver* observer) override;
+  void UnregisterMediaRoutesObserver(MediaRoutesObserver* observer) override;
+
+  // MediaRouteProviderManagerHost::Delegate implementation.
+  void OnMessage(const MediaRouteId& route_id,
+                 const std::string& message) override;
+  void OnSinksReceived(const MediaSource& source,
+                       const std::vector<MediaSink>& sinks) override;
+  void OnRouteResponseReceived(const RouteRequestId& request_id,
+                               const MediaRoute& route) override;
+  void OnRouteResponseError(const RouteRequestId& request_id,
+                            const std::string& error_text) override;
+  void OnRoutesUpdated(
+      const std::vector<MediaRoute>& routes,
+      const std::vector<MediaSink>& sinks) override;
+  void OnHostDestroyed(MediaRouteProviderManagerHost* host) override;
+
+ private:
+  friend class MediaRouterImplFactory;
+
+  // Use MediaRouterImplFactory::GetForBrowserContext().
+  MediaRouterImpl();
+
+  // MRPM host to forward calls to MRPM to.
+  // Responses from MRPM are also received from this host.
+  // Not owned by this object.
+  MediaRouteProviderManagerHost* mrpm_host_;

[xhwang, 2015/04/02 17:13:02]

Most people have no idea what "mrpm" is, use full name?

https://google-styleguide.googlecode.com/svn/trunk/cppguide.html#General_Nami...

BTW, a provider-manager-host sounds complicated ;)

[imcheng, 2015/04/02 23:05:24]

renamed to provider_manager_host_.

Yes, the class name is a bit wordy... It's the browser-side host for the Media
Route Provider Manager (MRPM), which is a manager of Media Route Providers (MRP)

+
+  DISALLOW_COPY_AND_ASSIGN(MediaRouterImpl);
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTER_IMPL_H_