Add initial GTK web accessibility framework (third attempt).

content/content_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.
 
 {
   'dependencies': [
     'browser/debugger/devtools_resources.gyp:devtools_resources',
     '../base/base.gyp:base_static',
     '../crypto/crypto.gyp:crypto',
     '../net/net.gyp:http_server',
@@ skipping 148 matching lines @@
     'public/browser/web_ui_controller_factory.h',
     'public/browser/web_ui_message_handler.h',
     'public/browser/worker_service.h',
     'public/browser/worker_service_observer.h',
     'public/browser/zygote_host_linux.h',
     'browser/accessibility/browser_accessibility.cc',
     'browser/accessibility/browser_accessibility.h',
     'browser/accessibility/browser_accessibility_cocoa.h',
     'browser/accessibility/browser_accessibility_cocoa.mm',
     'browser/accessibility/browser_accessibility_delegate_mac.h',
+    'browser/accessibility/browser_accessibility_gtk.cc',
+    'browser/accessibility/browser_accessibility_gtk.h',
     'browser/accessibility/browser_accessibility_mac.h',
     'browser/accessibility/browser_accessibility_mac.mm',
     'browser/accessibility/browser_accessibility_manager.cc',
     'browser/accessibility/browser_accessibility_manager.h',
+    'browser/accessibility/browser_accessibility_manager_gtk.cc',
+    'browser/accessibility/browser_accessibility_manager_gtk.h',
     'browser/accessibility/browser_accessibility_manager_mac.h',
     'browser/accessibility/browser_accessibility_manager_mac.mm',
     'browser/accessibility/browser_accessibility_manager_win.cc',
     'browser/accessibility/browser_accessibility_manager_win.h',
     'browser/accessibility/browser_accessibility_state_impl.cc',
     'browser/accessibility/browser_accessibility_state_impl.h',
     'browser/accessibility/browser_accessibility_win.cc',
     'browser/accessibility/browser_accessibility_win.h',
     'browser/android/library_loader_hooks.cc',
     'browser/appcache/appcache_dispatcher_host.cc',
@@ skipping 730 matching lines @@
       ],
     }],
     ['input_speech==0', {
       'sources/': [
         ['exclude', '^browser/speech/'],
       ],
     }],
   ],
 }