Use FileDescriptorWatcher in 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 365cac538b10a6843013db80cf7ac749fce4e9df..53205dd7ea5ab9332047645c0ed289df11ba55b1 100644
--- a/base/files/file_path_watcher_kqueue.h
+++ b/base/files/file_path_watcher_kqueue.h
@@ -6,8 +6,11 @@
 #define BASE_FILES_FILE_PATH_WATCHER_KQUEUE_H_
 
 #include <sys/event.h>
+
+#include <memory>
 #include <vector>
 
+#include "base/files/file_descriptor_watcher_posix.h"
 #include "base/files/file_path.h"
 #include "base/files/file_path_watcher.h"
 #include "base/macros.h"
@@ -28,15 +31,10 @@ namespace base {
 // files. It does however detect the attribute changes that the FSEvents impl
 // would miss.
 class FilePathWatcherKQueue : public FilePathWatcher::PlatformDelegate,
-                              public MessageLoopForIO::Watcher,
                               public MessageLoop::DestructionObserver {
  public:
   FilePathWatcherKQueue();
 
-  // MessageLoopForIO::Watcher overrides.
-  void OnFileCanReadWithoutBlocking(int fd) override;
-  void OnFileCanWriteWithoutBlocking(int fd) override;
-
   // MessageLoop::DestructionObserver overrides.
   void WillDestroyCurrentMessageLoop() override;
 
@@ -60,6 +58,9 @@ class FilePathWatcherKQueue : public FilePathWatcher::PlatformDelegate,
 
   typedef std::vector<struct kevent> EventVector;
 
+  // Called when data is available in |kqueue_|.
+  void OnKQueueReadable();
+
   // Can only be called on |io_task_runner_|'s thread.
   void CancelOnMessageLoopThread();
 
@@ -119,12 +120,14 @@ class FilePathWatcherKQueue : public FilePathWatcher::PlatformDelegate,
   }
 
   EventVector events_;
-  scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
-  MessageLoopForIO::FileDescriptorWatcher kqueue_watcher_;
   FilePathWatcher::Callback callback_;
   FilePath target_;
   int kqueue_;
 
+  // Throughout the lifetime of this, OnKQueueReadable() will be called when
+  // data is available in |kqueue_|.
+  std::unique_ptr<FileDescriptorWatcher::Controller> kqueue_watch_controller_;
+
   DISALLOW_COPY_AND_ASSIGN(FilePathWatcherKQueue);
 };