Allow FilePathWatcher to be used from sequenced tasks.

base/files/file_path_watcher_fsevents.cc

 // Copyright 2014 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_fsevents.h"
 
 #include <dispatch/dispatch.h>
 
 #include <list>
 
 #include "base/bind.h"
 #include "base/files/file_util.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/mac/scoped_cftyperef.h"
 #include "base/macros.h"
 #include "base/strings/stringprintf.h"
-#include "base/threading/thread_task_runner_handle.h"
+#include "base/threading/sequenced_task_runner_handle.h"
 
 namespace base {
 
 namespace {
 
 // The latency parameter passed to FSEventsStreamCreate().
 const CFAbsoluteTime kEventLatencySeconds = 0.3;
 
 // Resolve any symlinks in the path.
 FilePath ResolvePath(const FilePath& path) {
@@ skipping 50 matching lines @@
                                     bool recursive,
                                     const FilePathWatcher::Callback& callback) {
   DCHECK(!callback.is_null());
   DCHECK(callback_.is_null());
 
   // This class could support non-recursive watches, but that is currently
   // left to FilePathWatcherKQueue.
   if (!recursive)
     return false;
 
-  set_task_runner(ThreadTaskRunnerHandle::Get());
+  set_task_runner(SequencedTaskRunnerHandle::Get());
   callback_ = callback;
 
   FSEventStreamEventId start_event = FSEventsGetCurrentEventId();
   // The block runtime would implicitly capture the reference, not the object
   // it's referencing. Copy the path into a local, so that the value is
   // captured by the block's scope.
   const FilePath path_copy(path);
 
   dispatch_async(queue_, ^{
       StartEventStream(start_event, path_copy);
@@ skipping 165 matching lines @@
 void FilePathWatcherFSEvents::StartEventStream(FSEventStreamEventId start_event,
                                                const FilePath& path) {
   DCHECK(resolved_target_.empty());
 
   target_ = path;
   ResolveTargetPath();
   UpdateEventStream(start_event);
 }
 
 }  // namespace base