Remove ref-counting from FilePathWatcher.

base/files/file_path_watcher_fsevents.h

Index: base/files/file_path_watcher_fsevents.h
diff --git a/base/files/file_path_watcher_fsevents.h b/base/files/file_path_watcher_fsevents.h
index fbcca1f81010a56a6adc1272fe38b7f30670066b..dcdf2fbf9d172d5869543c394ee760dc6e4bc47a 100644
--- a/base/files/file_path_watcher_fsevents.h
+++ b/base/files/file_path_watcher_fsevents.h
@@ -14,6 +14,7 @@
 #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 {
 
@@ -26,6 +27,7 @@ namespace base {
 class FilePathWatcherFSEvents : public FilePathWatcher::PlatformDelegate {
  public:
   FilePathWatcherFSEvents();
+  ~FilePathWatcherFSEvents() override;
 
   // FilePathWatcher::PlatformDelegate overrides.
   bool Watch(const FilePath& path,
@@ -41,8 +43,6 @@ class FilePathWatcherFSEvents : public FilePathWatcher::PlatformDelegate {
                                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);
 
@@ -53,9 +53,6 @@ class FilePathWatcherFSEvents : public FilePathWatcher::PlatformDelegate {
                       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);
@@ -92,6 +89,8 @@ class FilePathWatcherFSEvents : public FilePathWatcher::PlatformDelegate {
   // (Only accessed from the libdispatch queue.)
   FSEventStreamRef fsevent_stream_;
 
+  WeakPtrFactory<FilePathWatcherFSEvents> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(FilePathWatcherFSEvents);
 };