Remove FilePathWatcher::PlatformDelegate::CancelOnMessageLoopThread().

base/files/file_path_watcher_fsevents.h

 // Copyright 2014 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 BASE_FILES_FILE_PATH_WATCHER_FSEVENTS_H_
 #define BASE_FILES_FILE_PATH_WATCHER_FSEVENTS_H_
 
 #include <CoreServices/CoreServices.h>
 #include <stddef.h>
 
@@ skipping 36 matching lines @@
   void OnFilePathsChanged(const std::vector<FilePath>& paths);
 
   // Called on the message_loop() thread to dispatch path events. Can't access
   // target_ and resolved_target_ directly as those are modified on the
   // libdispatch thread.
   void DispatchEvents(const std::vector<FilePath>& paths,
                       const FilePath& target,
                       const FilePath& resolved_target);
 
   // Cleans up and stops the event stream.
-  void CancelOnMessageLoopThread() override;
+  void CancelOnMessageLoopThread();
 
   // (Re-)Initialize the event stream to start reporting events from
   // |start_event|.
   void UpdateEventStream(FSEventStreamEventId start_event);
 
   // Returns true if resolving the target path got a different result than
   // last time it was done.
   bool ResolveTargetPath();
 
   // Report an error watching the given target.
@@ skipping 23 matching lines @@
   // Backend stream we receive event callbacks from (strong reference).
   // (Only accessed from the libdispatch queue.)
   FSEventStreamRef fsevent_stream_;
 
   DISALLOW_COPY_AND_ASSIGN(FilePathWatcherFSEvents);
 };
 
 }  // namespace base
 
 #endif  // BASE_FILES_FILE_PATH_WATCHER_FSEVENTS_H_