Introduce ChromeZoomLevelPref, make zoom level prefs independent of profile prefs.

chrome/chrome_browser_ui.gypi

 # Copyright 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.
 
 {
   'variables': {
     'chrome_browser_ui_non_ios_sources': [
       'browser/ui/accelerator_utils.h',
       'browser/ui/android/android_about_app_info.cc',
       'browser/ui/android/android_about_app_info.h',
@@ skipping 1110 matching lines @@
       'browser/ui/webui/version_handler_chromeos.cc',
       'browser/ui/webui/version_handler_chromeos.h',
       'browser/ui/webui/version_handler.h',
       'browser/ui/webui/version_ui.cc',
       'browser/ui/webui/version_ui.h',
       'browser/ui/webui/welcome_handler_android.cc',
       'browser/ui/webui/welcome_handler_android.h',
       'browser/ui/webui/welcome_ui_android.cc',
       'browser/ui/webui/welcome_ui_android.h',
       'browser/ui/window_sizer/window_sizer_mac.mm',
+      'browser/ui/zoom/chrome_zoom_level_prefs.cc',
+      'browser/ui/zoom/chrome_zoom_level_prefs.h',
       'browser/ui/zoom/zoom_controller.cc',
       'browser/ui/zoom/zoom_controller.h',
       'browser/ui/zoom/zoom_event_manager.cc',
       'browser/ui/zoom/zoom_event_manager.h',
       'browser/ui/zoom/zoom_observer.h',
     ],
     # Note that we assume app list is enabled on all views builds, so the
     # views-specific app list files are in the views section.
     'chrome_browser_ui_app_list_sources': [
       'browser/ui/views/app_list/app_list_dialog_container.cc',
@@ skipping 1856 matching lines @@
         }],
         ['OS!="android" and OS!="ios"', {
           'dependencies': [
             '../device/bluetooth/bluetooth.gyp:device_bluetooth',
           ],
         }],
       ],
     },
   ],
 }