Implement initial support for nesting one ax tree in another.

content/content_tests.gypi

 # Copyright (c) 2013 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': 'layouttest_support_content',
       'type': 'static_library',
       'conditions': [
@@ skipping 362 matching lines @@
       ],
       'include_dirs': [
         '..',
         '<(SHARED_INTERMEDIATE_DIR)',  # Needed by key_systems_unittest.cc.
       ],
       'sources': [
         'browser/accessibility/accessibility_mode_helper_unittest.cc',
         'browser/accessibility/browser_accessibility_mac_unittest.mm',
         'browser/accessibility/browser_accessibility_manager_unittest.cc',
         'browser/accessibility/browser_accessibility_win_unittest.cc',
+        'browser/accessibility/frame_tree_accessibility_unittest.cc',
         'browser/appcache/appcache_database_unittest.cc',
         'browser/appcache/appcache_disk_cache_unittest.cc',
         'browser/appcache/appcache_group_unittest.cc',
         'browser/appcache/appcache_host_unittest.cc',
         'browser/appcache/appcache_quota_client_unittest.cc',
         'browser/appcache/appcache_request_handler_unittest.cc',
         'browser/appcache/appcache_response_unittest.cc',
         'browser/appcache/appcache_service_unittest.cc',
         'browser/appcache/appcache_storage_unittest.cc',
         'browser/appcache/appcache_storage_impl_unittest.cc',
@@ skipping 1440 matching lines @@
                   'files': ['<(PRODUCT_DIR)/libnpapi_test_plugin.so'],
                 },
               ],
             }],
           ],
         },
       ],
     }],
   ],
 }