Presentation API: cleanup leftovers from .getAvailability() changes.

public/platform/modules/presentation/WebPresentationController.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 WebPresentationController_h
 #define WebPresentationController_h
 
 #include "public/platform/WebCommon.h"
 
 namespace blink {
 
 class WebPresentationSessionClient;
 class WebString;
 enum class WebPresentationSessionState;
 
 // The delegate Blink provides to WebPresentationClient in order to get updates.
 class BLINK_PLATFORM_EXPORT WebPresentationController {
 public:
     virtual ~WebPresentationController() { }
 
-    // Called when the presentation screen availability changes.
-    // May not be called if there's no registered listener for the event.
-    virtual void didChangeAvailability(bool available) = 0;
-
-    // Indicates if the frame has listeners to the |availablechange| event.
-    virtual bool isAvailableChangeWatched() const = 0;
-
     // Called when the presentation session is started by the embedder using
     // the default presentation URL and id.
     virtual void didStartDefaultSession(WebPresentationSessionClient*) = 0;
 
     // Called when the state of a session changes.
     virtual void didChangeSessionState(WebPresentationSessionClient*, WebPresentationSessionState) = 0;
 
     // Called when a text message of a session is received.
     virtual void didReceiveSessionTextMessage(WebPresentationSessionClient*, const WebString& message) = 0;
 };
 
 } // namespace blink
 
 #endif // WebPresentationController_h