Start work on GN build for content/common

ui/accessibility/BUILD.gn

+# 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.
+
+import("//extensions/generated_extensions_api.gni")
+
+component("accessibility") {
+  sources = [
+    "ax_node.cc",
+    "ax_node.h",
+    "ax_node_data.cc",
+    "ax_node_data.h",
+    "ax_serializable_tree.cc",
+    "ax_serializable_tree.h",
+    "ax_text_utils.cc",
+    "ax_text_utils.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",
+    "ax_view_state.cc",
+    "ax_view_state.h",
+  ]
+
+  defines = [ "ACCESSIBILITY_IMPLEMENTATION" ]
+
+  forward_dependent_configs_from = [ ":ax_gen" ]
+
+  deps = [
+    ":ax_gen",
+    "//base",
+    "//ui/gfx",
+    "//ui/gfx/geometry",
+  ]
+}
+
+test("accessibility_unittests") {
+  sources = [
+    "ax_generated_tree_unittest.cc",
+    "ax_tree_serializer_unittest.cc",
+    "ax_tree_unittest.cc",
+  ]
+
+  deps = [
+    ":accessibility",
+    "//base",
+    "//base/test:run_all_unittests",
+    "//testing/gtest",
+    "//ui/gfx",
+    "//ui/gfx/geometry",
+  ]
+}
+
+generated_extensions_api("ax_gen") {
+  sources = [ "ax_enums.idl" ]
+  root_namespace = ""
+  impl_dir = "."
+}