Presentation API: reject screen availability observing on Android low ram devices.

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>
 
@@ skipping 115 matching lines @@
   // 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
   // manage |observer| and make sure |UnregisterObserver()| is called
   // before the observer is destroyed.
   // It is invalid to register the same observer more than once and will result
   // in undefined behavior.
   // If the MRPM Host is not available, the registration request will fail
   // immediately.
-  virtual void RegisterMediaSinksObserver(MediaSinksObserver* observer) = 0;
+  // The implementation can reject the request to observe in which case it will
+  // notify the caller by returning |false|.
+  virtual bool RegisterMediaSinksObserver(MediaSinksObserver* observer) = 0;
 
   // Removes a previously added MediaSinksObserver. |observer| will stop
   // receiving further updates.
   virtual void UnregisterMediaSinksObserver(MediaSinksObserver* observer) = 0;
 
   // Adds a MediaRoutesObserver to listen for updates on MediaRoutes.
   // The initial update may happen synchronously.
   // MediaRouter does not own |observer|. |UnregisterMediaRoutesObserver| should
   // be called before |observer| is destroyed.
   // It is invalid to register the same observer more than once and will result
@@ skipping 23 matching lines @@
 
   // Unregisters a previously registered PresentationSessionMessagesObserver.
   // |observer| will stop receiving further updates.
   virtual void UnregisterPresentationSessionMessagesObserver(
       PresentationSessionMessagesObserver* observer) = 0;
 };
 
 }  // namespace media_router
 
 #endif  // CHROME_BROWSER_MEDIA_ROUTER_MEDIA_ROUTER_H_