Create base class for TabHelpers.

chrome/chrome_browser.gypi

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': 'static_library',
@@ skipping 2400 matching lines @@
         'browser/tab_contents/tab_util.h',
         'browser/tab_contents/thumbnail_generator.cc',
         'browser/tab_contents/thumbnail_generator.h',
         'browser/tab_contents/spellchecker_submenu_observer.h',
         'browser/tab_contents/spellchecker_submenu_observer_hunspell.cc',
         'browser/tab_contents/spellchecker_submenu_observer_mac.cc',
         'browser/tab_contents/spelling_bubble_model.cc',
         'browser/tab_contents/spelling_bubble_model.h',
         'browser/tab_contents/spelling_menu_observer.cc',
         'browser/tab_contents/spelling_menu_observer.h',
+        'browser/tab_contents/web_contents_user_data.h',
         'browser/tab_contents/web_drag_bookmark_handler_aura.cc',
         'browser/tab_contents/web_drag_bookmark_handler_aura.h',
         'browser/tab_contents/web_drag_bookmark_handler_gtk.cc',
         'browser/tab_contents/web_drag_bookmark_handler_gtk.h',
         'browser/tab_contents/web_drag_bookmark_handler_mac.h',
         'browser/tab_contents/web_drag_bookmark_handler_mac.mm',
         'browser/tab_contents/web_drag_bookmark_handler_win.cc',
         'browser/tab_contents/web_drag_bookmark_handler_win.h',
         'browser/task_manager/task_manager.cc',
         'browser/task_manager/task_manager.h',
@@ skipping 3220 matching lines @@
           'includes': [ '../build/jni_generator.gypi' ],
           'dependencies': [
             'android_jar_jni_headers',
           ],
         },
       ],
      },
     ],
   ],
 }