Install platform apps into a separate data directory

chrome/common/mac/app_mode_common.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/mac/app_mode_common.h"
 
 namespace app_mode {
 
 NSString* const kBrowserBundleIDKey = @"CrBundleIdentifier";
 const CFStringRef kLastRunAppBundlePathPrefsKey = CFSTR("LastRunAppBundlePath");
 
 NSString * const kCrAppModeShortcutIDKey = @"CrAppModeShortcutID";
 NSString * const kCrAppModeShortcutShortNameKey = @"CrAppModeShortcutShortName";
 NSString * const kCrAppModeShortcutNameKey = @"CrAppModeShortcutName";
 NSString * const kCrAppModeShortcutURLKey = @"CrAppModeShortcutURL";
+NSString * const kCrAppModeUserDataDirKey = @"CrAppModeUserDataDir";
 
 ChromeAppModeInfo::ChromeAppModeInfo() {
 }
 
 ChromeAppModeInfo::~ChromeAppModeInfo() {
 }
 
 }  // namespace app_mode