Define iTunes location for media galleries tests.

chrome/browser/media_galleries/fileapi/itunes_finder_mac.h

 // Copyright (c) 2013 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.
 
 #ifndef CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_ITUNES_FINDER_MAC_H_
 #define CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_ITUNES_FINDER_MAC_H_
 
 #include "chrome/browser/media_galleries/fileapi/itunes_finder.h"
 
+class MacPreferences;
+
 namespace itunes {
 
+extern const char kITunesRecentDatabasePathsKey[];
+
 class ITunesFinderMac : public ITunesFinder {
  public:
   explicit ITunesFinderMac(const ITunesFinderCallback& callback);
   virtual ~ITunesFinderMac();
 
+  static void SetMacPreferencesForTesting(MacPreferences* preferences);
+
  private:
   virtual void FindITunesLibraryOnFileThread() OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(ITunesFinderMac);
 };
 
 }  // namespace itunes
 
 #endif  // CHROME_BROWSER_MEDIA_GALLERIES_FILEAPI_ITUNES_FINDER_MAC_H_