Pass a TaskRunner through ViewsDelegate to put AX init on FILE thread

ui/accessibility/platform/atk_util_auralinux.cc

 // Copyright 2015 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.
 
 #include <atk/atk.h>
 #if defined(USE_GCONF)
 #include <gconf/gconf-client.h>
 #endif
 #include <glib-2.0/gmodule.h>
 
@@ skipping 122 matching lines @@
 //
 
 namespace ui {
 
 // static
 AtkUtilAuraLinux* AtkUtilAuraLinux::GetInstance() {
   return Singleton<AtkUtilAuraLinux>::get();
 }
 
 AtkUtilAuraLinux::AtkUtilAuraLinux() {
+}
+
+void AtkUtilAuraLinux::Initialize(
+    scoped_refptr<base::TaskRunner> init_task_runner) {
+  // TODO(k.czech): use |init_task_runner| to post a task to do the
+  // initialization rather than doing it on this thread.
+  // http://crbug.com/468112
+
   // Register our util class.
   g_type_class_unref(g_type_class_ref(ATK_UTIL_AURALINUX_TYPE));
 
   if (!ShouldEnableAccessibility()) {
     VLOG(1) << "Will not enable ATK accessibility support.";
     return;
   }
 
   VLOG(1) << "Enabling ATK accessibility support.";
 
@@ skipping 12 matching lines @@
   if (g_module_symbol(bridge, "gnome_accessibility_module_init",
                       (gpointer *)&gnome_accessibility_module_init)) {
     (*gnome_accessibility_module_init)();
   }
 }
 
 AtkUtilAuraLinux::~AtkUtilAuraLinux() {
 }
 
 }  // namespace ui