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

ui/views/views_delegate.cc

 // 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.
 
 #include "ui/views/views_delegate.h"
 
 #include "base/command_line.h"
 #include "ui/views/views_touch_selection_controller_factory.h"
 
 namespace views {
@@ skipping 73 matching lines @@
 
 ui::ContextFactory* ViewsDelegate::GetContextFactory() {
   return NULL;
 }
 
 std::string ViewsDelegate::GetApplicationName() {
   base::FilePath program = base::CommandLine::ForCurrentProcess()->GetProgram();
   return program.BaseName().AsUTF8Unsafe();
 }
 
+#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+scoped_refptr<base::TaskRunner>
+    ViewsDelegate::GetTaskRunnerForAuraLinuxAccessibilityInit() {
+  return nullptr;
+}
+#endif
+
 #if defined(OS_WIN)
 int ViewsDelegate::GetAppbarAutohideEdges(HMONITOR monitor,
                                           const base::Closure& callback) {
   return EDGE_BOTTOM;
 }
 #endif
 
 }  // namespace views