RefCounted types should not have public destructors, base/ edition

base/files/file_path_watcher_mac.cc

Index: base/files/file_path_watcher_mac.cc
diff --git a/base/files/file_path_watcher_mac.cc b/base/files/file_path_watcher_mac.cc
index 07a4dd287850bd7e8b9dd8e3b9729c16a3ff48d4..d5d31a0a9e85b3a35453ab97690276344eec78ba 100644
--- a/base/files/file_path_watcher_mac.cc
+++ b/base/files/file_path_watcher_mac.cc
@@ -46,7 +46,6 @@ class FilePathWatcherImpl : public FilePathWatcher::PlatformDelegate,
                             public MessageLoop::DestructionObserver {
  public:
   FilePathWatcherImpl() : kqueue_(-1) {}
-  virtual ~FilePathWatcherImpl() {}
 
   // MessageLoopForIO::Watcher overrides.
   virtual void OnFileCanReadWithoutBlocking(int fd) OVERRIDE;
@@ -60,6 +59,9 @@ class FilePathWatcherImpl : public FilePathWatcher::PlatformDelegate,
                      FilePathWatcher::Delegate* delegate) OVERRIDE;
   virtual void Cancel() OVERRIDE;
 
+ protected:
+  virtual ~FilePathWatcherImpl() {}
+
  private:
   class EventData {
    public: