Remove ref-counting from FilePathWatcher.

base/files/file_path_watcher_kqueue.h

Index: base/files/file_path_watcher_kqueue.h
diff --git a/base/files/file_path_watcher_kqueue.h b/base/files/file_path_watcher_kqueue.h
index 05e094189272da012eb3b4c97c6fb82aa7f2ffef..ef79be5596b87833fdebf2a34325e93ba8673a1e 100644
--- a/base/files/file_path_watcher_kqueue.h
+++ b/base/files/file_path_watcher_kqueue.h
@@ -31,6 +31,7 @@ namespace base {
 class FilePathWatcherKQueue : public FilePathWatcher::PlatformDelegate {
  public:
   FilePathWatcherKQueue();
+  ~FilePathWatcherKQueue() override;
 
   // FilePathWatcher::PlatformDelegate overrides.
   bool Watch(const FilePath& path,
@@ -38,9 +39,6 @@ class FilePathWatcherKQueue : public FilePathWatcher::PlatformDelegate {
              const FilePathWatcher::Callback& callback) override;
   void Cancel() override;
 
- protected:
-  ~FilePathWatcherKQueue() override;
-
  private:
   class EventData {
    public: