Add external extensions json source in proper mac location.

chrome/common/chrome_paths_mac.mm

 // Copyright (c) 2011 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 "chrome/common/chrome_paths_internal.h"
 
 #import <Foundation/Foundation.h>
 #include <string.h>
 
 #include <string>
@@ skipping 87 matching lines @@
     *result = result->Append(ProductDirName());
     success = true;
   }
   return success;
 }
 
 bool GetUserDocumentsDirectory(FilePath* result) {
   return base::mac::GetUserDirectory(NSDocumentDirectory, result);
 }
 
+bool GetGlobalApplicationSupportDirectory(FilePath* result) {
+  return base::mac::GetLocalDirectory(NSApplicationSupportDirectory, result);
+}
+
 void GetUserCacheDirectory(const FilePath& profile_dir, FilePath* result) {
   // If the profile directory is under ~/Library/Application Support,
   // use a suitable cache directory under ~/Library/Caches.  For
   // example, a profile directory of ~/Library/Application
   // Support/Google/Chrome/MyProfileName would use the cache directory
   // ~/Library/Caches/Google/Chrome/MyProfileName.
 
   // Default value in cases where any of the following fails.
   *result = profile_dir;
 
@@ skipping 71 matching lines @@
 }
 
 NSBundle* OuterAppBundle() {
   // Cache this. Foundation leaks it anyway, and this should be the only call
   // to OuterAppBundleInternal().
   static NSBundle* bundle = OuterAppBundleInternal();
   return bundle;
 }
 
 }  // namespace chrome