Move some accessibility methods, enums and interfaces into the content/public API.

content/content_common.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.
 
 {
   'dependencies': [
     '../base/base.gyp:base',
     '../build/temp_gyp/googleurl.gyp:googleurl',
     '../components/components_tracing.gyp:tracing',
     '../media/media.gyp:media',
     '../net/net.gyp:net',
     '../skia/skia.gyp:skia',
     '../third_party/icu/icu.gyp:icuuc',
     '../ui/ui.gyp:shell_dialogs',
     '../ui/ui.gyp:ui',
     '../webkit/support/webkit_support.gyp:user_agent',
   ],
   'include_dirs': [
     '..',
   ],
   'export_dependent_settings': [
     '../base/base.gyp:base',
   ],
   'sources': [
+    'public/common/accessibility_mode.h',
     'public/common/bindings_policy.h',
     'public/common/child_process_host.h',
     'public/common/child_process_host_delegate.cc',
     'public/common/child_process_host_delegate.h',
     'public/common/child_process_sandbox_support_linux.h',
     'public/common/content_constants.cc',
     'public/common/content_constants.h',
     'public/common/content_descriptors.h',
     'public/common/content_ipc_logging.h',
     'public/common/content_paths.h',
@@ skipping 541 matching lines @@
         '..\\third_party\\directxsdk\\files\\Redist\\<(input)',
         '<(output)',
         '<(PRODUCT_DIR)',
         ],
         'msvs_cygwin_shell': 1,
       },
      ]
     }],
   ],
 }