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

chrome/browser/media_galleries/fileapi/file_path_watcher_util.cc

Index: chrome/browser/media_galleries/fileapi/file_path_watcher_util.cc
diff --git a/chrome/browser/media_galleries/fileapi/file_path_watcher_util.cc b/chrome/browser/media_galleries/fileapi/file_path_watcher_util.cc
index 16295c999a16981a1e4be8aea330e3473538a13e..129cbac2d16058cb095745103d25cfa13e7188c5 100644
--- a/chrome/browser/media_galleries/fileapi/file_path_watcher_util.cc
+++ b/chrome/browser/media_galleries/fileapi/file_path_watcher_util.cc
@@ -58,15 +58,3 @@
                                               watch_started_callback,
                                               path_changed_callback));
 }
-
-void StopFilePathWatchOnMediaTaskRunner(
-    std::unique_ptr<base::FilePathWatcher> watcher) {
-  MediaFileSystemBackend::AssertCurrentlyOnMediaSequence();
-  if (watcher) {
-    const bool task_posted = content::BrowserThread::DeleteSoon(
-        content::BrowserThread::FILE, FROM_HERE, watcher.release());
-
-    // This will fail if the FILE thread has been stopped.
-    DCHECK(task_posted);
-  }
-}