Remove destruction observer from base::FilePathWatcherKQueue.

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 53205dd7ea5ab9332047645c0ed289df11ba55b1..9095f14dbdeeafbf124869a6b0ddafda60bfd2b1 100644
--- a/base/files/file_path_watcher_kqueue.h
+++ b/base/files/file_path_watcher_kqueue.h
@@ -14,7 +14,6 @@
 #include "base/files/file_path.h"
 #include "base/files/file_path_watcher.h"
 #include "base/macros.h"
-#include "base/message_loop/message_loop.h"
 #include "base/single_thread_task_runner.h"
 
 namespace base {
@@ -30,14 +29,10 @@ namespace base {
 // detect the creation and deletion of files, just not the modification of
 // files. It does however detect the attribute changes that the FSEvents impl
 // would miss.
-class FilePathWatcherKQueue : public FilePathWatcher::PlatformDelegate,
-                              public MessageLoop::DestructionObserver {
+class FilePathWatcherKQueue : public FilePathWatcher::PlatformDelegate {
  public:
   FilePathWatcherKQueue();
 
-  // MessageLoop::DestructionObserver overrides.
-  void WillDestroyCurrentMessageLoop() override;
-
   // FilePathWatcher::PlatformDelegate overrides.
   bool Watch(const FilePath& path,
              bool recursive,
@@ -61,9 +56,6 @@ class FilePathWatcherKQueue : public FilePathWatcher::PlatformDelegate,
   // Called when data is available in |kqueue_|.
   void OnKQueueReadable();
 
-  // Can only be called on |io_task_runner_|'s thread.
-  void CancelOnMessageLoopThread();
-
   // Returns true if the kevent values are error free.
   bool AreKeventValuesValid(struct kevent* kevents, int count);