[Media Router] Notify MRUI of a media status update when it starts observing

chrome/browser/media/router/mojo/media_route_controller.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_MOJO_MEDIA_ROUTE_CONTROLLER_H_
 #define CHROME_BROWSER_MEDIA_ROUTER_MOJO_MEDIA_ROUTE_CONTROLLER_H_
 
 #include <memory>
 
 #include "base/memory/ref_counted.h"
@@ skipping 34 matching lines @@
     virtual ~Observer();
 
     virtual void OnMediaStatusUpdated(const MediaStatus& status) = 0;
 
     // Returns a reference to the observed MediaRouteController. The reference
     // should not be stored by any object that does not subclass ::Observer.
     scoped_refptr<MediaRouteController> controller() const {
       return controller_;
     }
 
+   protected:
+    scoped_refptr<MediaRouteController> controller_;
+
    private:
     friend class MediaRouteController;
 
     // Disposes the reference to the controller.
     void InvalidateController();
 
     // Called by InvalidateController() after the reference to the controller is
     // disposed. Overridden by subclasses to do custom cleanup.
     virtual void OnControllerInvalidated();
 
-    scoped_refptr<MediaRouteController> controller_;
-
     DISALLOW_COPY_AND_ASSIGN(Observer);
   };
 
   // Constructs a MediaRouteController that forwards media commands to
   // |mojo_media_controller|. |media_router| will be notified when the
   // MediaRouteController is destroyed via DetachRouteController().
   MediaRouteController(const MediaRoute::Id& route_id,
                        mojom::MediaControllerPtr mojo_media_controller,
                        MediaRouter* media_router);
 
@@ skipping 12 matching lines @@
   // Notifies |observers_| to dispose their references to the controller. The
   // controller gets destroyed when all the references are disposed.
   void Invalidate();
 
   // Returns a mojo pointer bound to |this| by |binding_|. This must only be
   // called at most once in the lifetime of the controller.
   mojom::MediaStatusObserverPtr BindObserverPtr();
 
   MediaRoute::Id route_id() const { return route_id_; }
 
+  const base::Optional<MediaStatus>& current_media_status() const {

[mark a. foltz, 2017/05/12 23:06:18]

Document this method

[takumif, 2017/05/15 17:57:29]

Done.

+    return current_media_status_;
+  }
+
  protected:
   ~MediaRouteController() override;
 
  private:
   friend class base::RefCounted<MediaRouteController>;
 
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
   // Called when the connection between |this| and the MediaControllerPtr or
@@ skipping 13 matching lines @@
   // The binding to observe the out-of-process provider of status updates.
   mojo::Binding<mojom::MediaStatusObserver> binding_;
 
   // Observers that are notified of status updates. The observers share the
   // ownership of the controller through scoped_refptr.
   base::ObserverList<Observer> observers_;
 
   // This becomes false when the controller is invalidated.
   bool is_valid_ = true;
 
+  // The latest media status that the controller has been notified with.
+  base::Optional<MediaStatus> current_media_status_;
+
   DISALLOW_COPY_AND_ASSIGN(MediaRouteController);
 };
 
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_MEDIA_ROUTER_MOJO_MEDIA_ROUTE_CONTROLLER_H_