Add FilePath to base namespace.

media/base/media_stub.cc

 // Copyright 2012 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 "media/base/media.h"
 
 #include "base/logging.h"
 
 // This file is intended for platforms that don't need to load any media
 // libraries (e.g., Android and iOS).
 namespace media {
 
-bool InitializeMediaLibrary(const FilePath& module_dir) {
+bool InitializeMediaLibrary(const base::FilePath& module_dir) {
   return true;
 }
 
 void InitializeMediaLibraryForTesting() {
 }
 
 bool IsMediaLibraryInitialized() {
   return true;
 }
 
 }  // namespace media