Remove ref-counting from FilePathWatcher.

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>
 
 #include <vector>
 
 #include "base/files/file_path.h"
 #include "base/files/file_path_watcher.h"
 #include "base/mac/scoped_dispatch_object.h"
 #include "base/macros.h"
+#include "base/memory/weak_ptr.h"
 
 namespace base {
 
 // Mac-specific file watcher implementation based on FSEvents.
 // There are trade-offs between the FSEvents implementation and a kqueue
 // implementation. The biggest issues are that FSEvents on 10.6 sometimes drops
 // events and kqueue does not trigger for modifications to a file in a watched
 // directory. See file_path_watcher_mac.cc for the code that decides when to
 // use which one.
 class FilePathWatcherFSEvents : public FilePathWatcher::PlatformDelegate {
  public:
   FilePathWatcherFSEvents();
+  ~FilePathWatcherFSEvents() override;
 
   // FilePathWatcher::PlatformDelegate overrides.
   bool Watch(const FilePath& path,
              bool recursive,
              const FilePathWatcher::Callback& callback) override;
   void Cancel() override;
 
  private:
   static void FSEventsCallback(ConstFSEventStreamRef stream,
                                void* event_watcher,
                                size_t num_events,
                                void* event_paths,
                                const FSEventStreamEventFlags flags[],
                                const FSEventStreamEventId event_ids[]);
 
-  ~FilePathWatcherFSEvents() override;
-
   // Called from FSEventsCallback whenever there is a change to the paths.
   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();
-
   // (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.
   void ReportError(const FilePath& target);
@@ skipping 16 matching lines @@
   FilePath target_;
 
   // Target path with all symbolic links resolved.
   // (Only accessed from the libdispatch queue.)
   FilePath resolved_target_;
 
   // Backend stream we receive event callbacks from (strong reference).
   // (Only accessed from the libdispatch queue.)
   FSEventStreamRef fsevent_stream_;
 
+  WeakPtrFactory<FilePathWatcherFSEvents> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(FilePathWatcherFSEvents);
 };
 
 }  // namespace base
 
 #endif  // BASE_FILES_FILE_PATH_WATCHER_FSEVENTS_H_