MediaRouterAction: Only observe Media Routes when there is a local route.

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 "base/callback.h"
 #include "base/memory/scoped_vector.h"
 #include "chrome/browser/media/router/issue.h"
 #include "chrome/browser/media/router/media_route.h"
 #include "chrome/browser/media/router/media_sink.h"
 #include "chrome/browser/media/router/media_source.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "content/public/browser/presentation_session_message.h"
 
 namespace media_router {
 
 class IssuesObserver;
+class LocalMediaRoutesObserver;
 class MediaRoutesObserver;
 class MediaSinksObserver;
 class PresentationSessionMessagesObserver;
 
 // Type of callback used in |CreateRoute()| and |JoinRoute()|. Callback is
 // invoked when the route request either succeeded or failed.
 // On success:
 // |route|: The route created or joined.
 // |presentation_id|:
 //     The presentation ID of the route created or joined. In the case of
@@ skipping 75 matching lines @@
   virtual void AddIssue(const Issue& issue) = 0;
 
   // Clears the issue with the id |issue_id|.
   virtual void ClearIssue(const Issue::Id& issue_id) = 0;
 
   // Indicates that a presentation session has detached from the underlying
   // MediaRoute |route_id| (due to navigation, garbage collection, etc.)
   virtual void OnPresentationSessionDetached(
       const MediaRoute::Id& route_id) = 0;
 
+  // Returns whether or not there is currently an active local route.
+  virtual bool HasLocalRoute() const = 0;
+
  private:
   friend class IssuesObserver;
+  friend class LocalMediaRoutesObserver;
   friend class MediaSinksObserver;
   friend class MediaRoutesObserver;
   friend class PresentationSessionMessagesObserver;
 
   // The following functions are called by friend Observer classes above.
 
   // Registers |observer| with this MediaRouter. |observer| specifies a media
   // source and will receive updates with media sinks that are compatible with
   // that source. The initial update may happen synchronously.
   // NOTE: This class does not assume ownership of |observer|. Callers must
@@ skipping 35 matching lines @@
   // |observer|. |observer| should be unregistered before it is destroyed.
   // Registering the same observer more than once will result in undefined
   // behavior.
   virtual void RegisterPresentationSessionMessagesObserver(
       PresentationSessionMessagesObserver* observer) = 0;
 
   // Unregisters a previously registered PresentationSessionMessagesObserver.
   // |observer| will stop receiving further updates.
   virtual void UnregisterPresentationSessionMessagesObserver(
       PresentationSessionMessagesObserver* observer) = 0;
+
+  // Adds the LocalMediaRoutesObserver |observer| to listen for newly created
+  // MediaRoutes.
+  virtual void RegisterLocalMediaRoutesObserver(
+      LocalMediaRoutesObserver* observer) = 0;
+
+  // Removes the LocalMediaRoutesObserver |observer|.
+  virtual void UnregisterLocalMediaRoutesObserver(
+      LocalMediaRoutesObserver* observer) = 0;
 };
 
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTER_H_