Remove FilePathWatcher::PlatformDelegate::CancelOnMessageLoopThread().

base/files/file_path_watcher_win.cc

Index: base/files/file_path_watcher_win.cc
diff --git a/base/files/file_path_watcher_win.cc b/base/files/file_path_watcher_win.cc
index f2de78343ef09669ebe39c69b2bbacaa32da90fe..f9b1b1c545c5791c42bf1251316f245967bd7022 100644
--- a/base/files/file_path_watcher_win.cc
+++ b/base/files/file_path_watcher_win.cc
@@ -59,7 +59,7 @@ class FilePathWatcherImpl : public FilePathWatcher::PlatformDelegate,
   void DestroyWatch();
 
   // Cleans up and stops observing the |task_runner_| thread.
-  void CancelOnMessageLoopThread() override;
+  void CancelOnMessageLoopThread();
 
   // Callback to notify upon changes.
   FilePathWatcher::Callback callback_;
@@ -121,8 +121,8 @@ void FilePathWatcherImpl::Cancel() {
 
   // Switch to the file thread if necessary so we can stop |watcher_|.
   if (!task_runner()->BelongsToCurrentThread()) {
-    task_runner()->PostTask(FROM_HERE, Bind(&FilePathWatcher::CancelWatch,
-                                            make_scoped_refptr(this)));
+    task_runner()->PostTask(
+        FROM_HERE, Bind(&FilePathWatcherImpl::CancelOnMessageLoopThread, this));
   } else {
     CancelOnMessageLoopThread();
   }