mash: Change CastConfigDelegate to a mojoified CastConfigClient.

ash/test/tray_cast_test_api.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 ASH_TEST_TRAY_CAST_TEST_API_H_
 #define ASH_TEST_TRAY_CAST_TEST_API_H_
 
 #include <string>
 
 #include "ash/ash_export.h"
@@ skipping 23 matching lines @@
 
   // Start a new cast to the given receiver.
   void StartCast(const std::string& receiver_id);
   void StopCast();
 
   // Exposed callback to update the casting state. The test code needs to call
   // this function manually, as there is no actual casting going on. In a real
   // environment, this method is invoked by the casting system in Chrome.
   void OnCastingSessionStartedOrStopped(bool is_casting);
 
-  // Release callback hooks in config delegate. They will get re-registered if
-  // the tray is used again.
-  void ReleaseConfigCallbacks();
-
  private:
   bool IsViewDrawn(TrayCast::ChildViewId id) const;
 
   // Not owned.
   TrayCast* tray_cast_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayCastTestAPI);
 };
 
 }  // namespace ash
 
 #endif  // ASH_TEST_TRAY_CAST_TEST_API_H_