Require FilePathWatcher destructor to be called in sequence with Watch().

chrome/browser/media_galleries/fileapi/file_path_watcher_util.h

Index: chrome/browser/media_galleries/fileapi/file_path_watcher_util.h
diff --git a/chrome/browser/media_galleries/fileapi/file_path_watcher_util.h b/chrome/browser/media_galleries/fileapi/file_path_watcher_util.h
index 8e512534c8c5d3300086b83daf0c3f71dfff44df..2d60ade59d68f2b4bd75f44f9730d8da9caff3dd 100644
--- a/chrome/browser/media_galleries/fileapi/file_path_watcher_util.h
+++ b/chrome/browser/media_galleries/fileapi/file_path_watcher_util.h
@@ -22,4 +22,9 @@ void StartFilePathWatchOnMediaTaskRunner(
     const FileWatchStartedCallback& watch_started_callback,
     const base::FilePathWatcher::Callback& path_changed_callback);
 
+// Stops a file path watch started by StartFilePathWatchOnMediaTaskRunner. Must

[Lei Zhang, 2016/11/10 18:59:31]

nit: I really like to refer to functions as FuncName() so it is obvious that it
is a function and not a class.

[fdoray, 2016/11/11 15:47:39]

Done.

+// be called from the MediaTaskRunner.
+void StopFilePathWatchOnMediaTaskRunner(
+    std::unique_ptr<base::FilePathWatcher> watcher);
+
 #endif  // CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_FILE_PATH_WATCHER_UTIL_H_