First step to move common accessibility code out of content.

ui/accessibility/accessibility.gyp

+# 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.
+
+{
+  'variables': {
+    'chromium_code': 1,
+  },
+
+  'targets': [
+    {
+      'target_name': 'accessibility',
+      'type': '<(component)',
+      'dependencies': [
+        '../../base/base.gyp:base',
+        '../gfx/gfx.gyp:gfx',
+      ],
+      'defines': [
+        'ACCESSIBILITY_IMPLEMENTATION',
+      ],
+      'sources': [
+        # All .cc, .h under accessibility, except unittests
+        'ax_enums.h',
+        'ax_node.cc',
+        'ax_node_data.cc',
+        'ax_node_data.h',
+        'ax_node.h',
+        'ax_serializable_tree.cc',
+        'ax_serializable_tree.h',
+        'ax_tree.cc',
+        'ax_tree.h',
+        'ax_tree_serializer.cc',
+        'ax_tree_serializer.h',
+        'ax_tree_source.h',
+        'ax_tree_update.cc',
+        'ax_tree_update.h',
+      ]
+    },
+    {
+      'target_name': 'accessibility_unittests',
+      'type': 'executable',
+      'dependencies': [
+        '../../base/base.gyp:base',
+        '../../base/base.gyp:test_support_base',
+        '../../testing/gtest.gyp:gtest',
+        '../../testing/gtest.gyp:gtest_main',
+        'accessibility',
+      ],
+      'sources': [
+        'ax_tree_unittest.cc',
+      ]
+    },
+  ],
+}