Install platform apps into a separate data directory

chrome/common/mac/app_mode_common.mm

 // Copyright (c) 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 "chrome/common/mac/app_mode_common.h"
 
 namespace app_mode {
 
 NSString* const kBrowserBundleIDKey = @"CrBundleIdentifier";
 NSString* const kLastRunAppBundlePathPrefsKey = @"LastRunAppBundlePath";
 NSString* const kCrAppModeShortcutIDKey = @"CrAppModeShortcutID";
 NSString* const kCrAppModeShortcutShortNameKey = @"CrAppModeShortcutShortName";
 NSString* const kCrAppModeShortcutNameKey = @"CrAppModeShortcutName";
 NSString* const kCrAppModeShortcutURLKey = @"CrAppModeShortcutURL";
 NSString* const kCrAppModeUserDataDirKey = @"CrAppModeUserDataDir";
+NSString* const kCrAppModeExtensionPathKey = @"CrAppModeExtensionPath";
 
 ChromeAppModeInfo::ChromeAppModeInfo()
     : major_version(0),
       minor_version(0),
       argc(0),
       argv(0) {
 }
 
 ChromeAppModeInfo::~ChromeAppModeInfo() {
 }
 
 }  // namespace app_mode