Remove ref-counting from FilePathWatcher.

base/files/file_path_watcher_win.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/files/file_path_watcher.h"
 
 #include "base/bind.h"
 #include "base/files/file.h"
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/logging.h"
 #include "base/macros.h"
+#include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/threading/sequenced_task_runner_handle.h"
 #include "base/time/time.h"
 #include "base/win/object_watcher.h"
 
 namespace base {
 
 namespace {
 
 class FilePathWatcherImpl : public FilePathWatcher::PlatformDelegate,
                             public base::win::ObjectWatcher::Delegate {
  public:
   FilePathWatcherImpl()
       : handle_(INVALID_HANDLE_VALUE),
         recursive_watch_(false) {}
+  ~FilePathWatcherImpl() override;
 
   // FilePathWatcher::PlatformDelegate:
   bool Watch(const FilePath& path,
              bool recursive,
              const FilePathWatcher::Callback& callback) override;
   void Cancel() override;
 
   // base::win::ObjectWatcher::Delegate:
   void OnObjectSignaled(HANDLE object) override;
 
  private:
-  ~FilePathWatcherImpl() override {}
-
   // Setup a watch handle for directory |dir|. Set |recursive| to true to watch
   // the directory sub trees. Returns true if no fatal error occurs. |handle|
   // will receive the handle value if |dir| is watchable, otherwise
   // INVALID_HANDLE_VALUE.
   static bool SetupWatchHandle(const FilePath& dir,
                                bool recursive,
                                HANDLE* handle) WARN_UNUSED_RESULT;
 
   // (Re-)Initialize the watch handle.
   bool UpdateWatch() WARN_UNUSED_RESULT;
@@ skipping 20 matching lines @@
   // to represent the file not existing.
   Time last_modified_;
 
   // The time at which we processed the first notification with the
   // |last_modified_| time stamp.
   Time first_notification_;
 
   DISALLOW_COPY_AND_ASSIGN(FilePathWatcherImpl);
 };
 
+FilePathWatcherImpl::~FilePathWatcherImpl() {
+  DCHECK(!task_runner() || task_runner()->RunsTasksOnCurrentThread());
+}
+
 bool FilePathWatcherImpl::Watch(const FilePath& path,
                                 bool recursive,
                                 const FilePathWatcher::Callback& callback) {
   DCHECK(target_.value().empty());  // Can only watch one path.
 
   set_task_runner(SequencedTaskRunnerHandle::Get());
   callback_ = callback;
   target_ = path;
   recursive_watch_ = recursive;
 
@@ skipping 171 matching lines @@
 void FilePathWatcherImpl::DestroyWatch() {
   watcher_.StopWatching();
   FindCloseChangeNotification(handle_);
   handle_ = INVALID_HANDLE_VALUE;
 }
 
 }  // namespace
 
 FilePathWatcher::FilePathWatcher() {
   sequence_checker_.DetachFromSequence();
-  impl_ = new FilePathWatcherImpl();
+  impl_ = MakeUnique<FilePathWatcherImpl>();
 }
 
 }  // namespace base