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

chrome/browser/media_galleries/fileapi/picasa_data_provider.cc

Index: chrome/browser/media_galleries/fileapi/picasa_data_provider.cc
diff --git a/chrome/browser/media_galleries/fileapi/picasa_data_provider.cc b/chrome/browser/media_galleries/fileapi/picasa_data_provider.cc
index 15275cc21e8b50c52d84ef79728c8021aee6ce7a..04360a930e6ce2e763f76a9ece40c96cc29373ce 100644
--- a/chrome/browser/media_galleries/fileapi/picasa_data_provider.cc
+++ b/chrome/browser/media_galleries/fileapi/picasa_data_provider.cc
@@ -51,9 +51,7 @@
                  weak_factory_.GetWeakPtr()));
 }
 
-PicasaDataProvider::~PicasaDataProvider() {
-  StopFilePathWatchOnMediaTaskRunner(std::move(temp_dir_watcher_));
-}
+PicasaDataProvider::~PicasaDataProvider() {}
 
 void PicasaDataProvider::RefreshData(DataType needed_data,
                                      const ReadyCallback& ready_callback) {