Move favicon callbacks to favicon_base

components/favicon_base.gypi

 # Copyright 2014 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': 'favicon_base',
       'type': 'static_library',
       'dependencies': [
         '../base/base.gyp:base',
         '../skia/skia.gyp:skia',
         '../ui/gfx/gfx.gyp:gfx',
         '../url/url.gyp:url_lib',
       ],
       'sources': [
+        'favicon_base/favicon_callback.h',
         'favicon_base/favicon_types.cc',
         'favicon_base/favicon_types.h',
         'favicon_base/select_favicon_frames.cc',
         'favicon_base/select_favicon_frames.h',
       ],
       'include_dirs': [
         '..',
       ],
     },
   ],
 }