[Media Router] Add Media Router Mojo impl code.

chrome/browser/media/router/media_router_mojo_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_MOJO_IMPL_H_
+#define CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTER_MOJO_IMPL_H_
+
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/containers/hash_tables.h"
+#include "base/containers/scoped_ptr_hash_map.h"
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/message_loop/message_loop_proxy.h"
+#include "base/observer_list.h"
+#include "base/threading/thread_checker.h"
+#include "chrome/browser/media/router/issue.h"
+#include "chrome/browser/media/router/media_router.h"
+#include "chrome/browser/media/router/media_router.mojom.h"
+#include "components/keyed_service/core/keyed_service.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace extensions {
+class EventPageTracker;
+}
+
+namespace media_router {
+
+// Mojo service exposing Media Router functionality to the Media Route Provider
+// Manager.
+class MediaRouterMojoImpl : public MediaRouter,
+                            public interfaces::MediaRouterObserver,
+                            public mojo::ErrorHandler,
+                            public KeyedService {
+ public:
+  ~MediaRouterMojoImpl() override;
+
+  // Binds the MediaRouterMojoImpl BrowserContext service to a Mojo request.
+  // Called by the Mojo module registry.
+  // Stores the |extension_id| of the component extension in
+  // the MediaRouterMojoImpl instance.
+  // Also stores a reference to the extension's ProcessManager using

[Wez, 2015/05/23 00:45:47]

Let's re-word this to make clear what "binding to a request" actually means -
forget about the Mojo internals; what is it that this actually handles, e.g. is
it the handler for when the extension requests the MediaRouterObserver
interface, through which to call back to the MediaRouterMojoImpl?

[imcheng (use chromium acct), 2015/05/26 17:58:31]

Done.

+  // |context|, which is a reference to the BrowserContext that owns this
+  // instance and extension.
+  // |extension_id|: The ID of the component extension, used for querying
+  //     suspension state.
+  // |context|: The BrowserContext which owns the extension process.
+  // |request|: The Mojo connection request used for binding.
+  static void BindToRequest(
+      const std::string& extension_id,
+      content::BrowserContext* context,
+      mojo::InterfaceRequest<interfaces::MediaRouterObserver> request);
+
+  // mojo::ErrorHandler implementation.
+  void OnConnectionError() override;
+
+  // interfaces::MediaRouterObserver implementation.

[Wez, 2015/05/23 00:45:47]

So IIUC this is the implementation of the Mojo interface from extension->MR, so
it's not intended to be called directly by C++ code - I'd therefore move it to
the protected or private section. Same for mojo::ErrorHandler. That will make it
clearer that this object's public interface is MediaRouter.

[imcheng (use chromium acct), 2015/05/26 17:58:31]

Done.

+  void ProvideMediaRouter(
+      interfaces::MediaRouterPtr media_router_ptr,
+      const interfaces::MediaRouterObserver::ProvideMediaRouterCallback&
+          callback) override;
+  void OnMessage(const mojo::String& route_id,
+                 const mojo::String& message) override;
+  void OnIssue(interfaces::IssuePtr issue) override;
+  void OnSinksReceived(const mojo::String& media_source,
+                       mojo::Array<interfaces::MediaSinkPtr> sinks) override;
+  void OnRoutesUpdated(mojo::Array<interfaces::MediaRoutePtr> routes) override;
+
+  // MediaRouter implementation.
+  // Execution of the requests is delegated to the Do* methods, which can be
+  // enqueued for later use if the extension is temporarily suspended.
+  void CreateRoute(const MediaSourceId& source_id,
+                   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;
+  void ClearIssue(const Issue::IssueId& issue_id) override;
+  void RegisterMediaSinksObserver(MediaSinksObserver* observer) override;
+  void UnregisterMediaSinksObserver(MediaSinksObserver* observer) override;
+  void RegisterMediaRoutesObserver(MediaRoutesObserver* observer) override;
+  void UnregisterMediaRoutesObserver(MediaRoutesObserver* observer) override;
+  void AddIssuesObserver(IssuesObserver* observer) override;
+  void RemoveIssuesObserver(IssuesObserver* observer) override;
+
+ private:
+  friend class MediaRouterMojoImplFactory;
+  friend class MediaRouterMojoTest;
+
+  FRIEND_TEST_ALL_PREFIXES(MediaRouterMojoExtensionTest,
+                           DeferredBindingAndSuspension);
+
+  // Standard constructor, used by
+  // MediaRouterMojoImplFactory::GetApiForBrowserContext.
+  MediaRouterMojoImpl();
+
+  // Constructor used only for testing.
+  MediaRouterMojoImpl(
+      const std::string& mojo_media_router_ext_id,
+      extensions::EventPageTracker* event_page_tracker_for_test);
+
+  // Binds |this| to a Mojo interface request, so that clients can acquire a
+  // handle to a MediaRouterMojoImpl instance via the Mojo service connector.
+  void BindToMojoRequest(
+      mojo::InterfaceRequest<interfaces::MediaRouterObserver> request);
+
+  void InitExtensionInfo(const std::string& extension_id,
+                         content::BrowserContext* context);
+
+  // Enqueues a closure for later execution by ExecutePendingRequests().
+  void EnqueueTask(const base::Closure& closure);
+
+  // Runs a closure if the extension monitored by |extension_monitor_| is
+  // active, or defers it for later execution if the extension is suspended.
+  void RunOrDefer(const base::Closure& request);
+
+  // Dispatches the Mojo requests queued in |pending_requests_|.
+  void ExecutePendingRequests();
+
+  // These calls invoke methods in the MRPM via Mojo.
+  void DoCreateRoute(const MediaSourceId& source_id,
+                     const MediaSinkId& sink_id,
+                     const MediaRouteResponseCallback& callback);
+  void DoCloseRoute(const MediaRouteId& route_id);
+  void DoPostMessage(const MediaRouteId& route_id, const std::string& message);
+  void DoClearIssue(const Issue::IssueId& issue_id);
+  void DoStartObservingMediaSinks(const std::string& source_id);
+  void DoStopObservingMediaSinks(const std::string& source_id);
+  void DoStartObservingMediaRoutes();
+  void DoStopObservingMediaRoutes();
+  void DoStartObservingIssues();
+  void DoStopObservingIssues();
+
+  // Pending requests queued to be executed once MRPM becomes ready.
+  std::vector<base::Closure> pending_requests_;
+
+  base::ScopedPtrHashMap<MediaSourceId,
+                         scoped_ptr<ObserverList<MediaSinksObserver>>>
+      sinks_observers_;
+
+  ObserverList<MediaRoutesObserver> routes_observers_;
+
+  // Binds |this| to listen for updates from the component extension Media
+  // Router.
+  scoped_ptr<mojo::Binding<interfaces::MediaRouterObserver>> binding_;
+
+  // Mojo proxy object for the component extension Media Router.
+  // Set to null initially, and set to the proxy to the component extension
+  // on |ProvideMediaRouter()|. This is set to null again when the component
+  // extension becomes suspended or if there is a connection error.
+  interfaces::MediaRouterPtr mojo_media_router_;
+
+  // Id of the component extension. Used for managing its suspend/wake state
+  // via event_page_tracker_.
+  std::string mojo_media_router_extension_id_;
+
+  // Allows the extension to be monitored for suspend, and woken.
+  // This is a reference to a BrowserContext keyed service that outlives this
+  // instance.
+  extensions::EventPageTracker* event_page_tracker_;
+
+  // GUID unique to each browser run. Component extension uses this to detect
+  // when its persisted state was written by an older browser instance, and is
+  // therefore stale.
+  std::string instance_id_;
+
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(MediaRouterMojoImpl);
+};
+
+}  // namespace media_router
+
+#endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTER_MOJO_IMPL_H_