Clean up browser_resources.grd:...

chrome/browser/resources/media_common.js

-// Copyright (c) 2010 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.
-
-function pathIsVideoFile(path) {
-  return /\.(mp4|ogg|mpg|avi|mov)$/i.test(path);
-}
-
-function pathIsAudioFile(path) {
-  return /\.(mp3|m4a|wav)$/i.test(path);
-}
-
-function pathIsImageFile(path) {
-  return /\.(jpg|png|gif)$/i.test(path);
-}
-
-function pathIsHtmlFile(path) {
-  return /\.(htm|html|txt)$/i.test(path);
-}