Revert "Enable chrome.automation.getDesktop on all aura platforms."

chrome/browser/ui/ash/accessibility/ax_root_obj_wrapper.cc

 // 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.
 
-#include "chrome/browser/ui/aura/accessibility/ax_root_obj_wrapper.h"
+#include "chrome/browser/ui/ash/accessibility/ax_root_obj_wrapper.h"
 
+#include "ash/shell.h"
 #include "base/strings/utf_string_conversions.h"
 #include "ui/accessibility/ax_node_data.h"
 #include "ui/accessibility/ax_view_state.h"
 #include "ui/aura/window.h"
 #include "ui/views/accessibility/ax_aura_obj_cache.h"
 #include "ui/views/accessibility/ax_window_obj_wrapper.h"
 
 AXRootObjWrapper::AXRootObjWrapper(int32 id)
     : id_(id), alert_window_(new aura::Window(NULL)) {
 }
@@ skipping 20 matching lines @@
   GetChildren(&children);
   return std::find(children.begin(), children.end(), child) != children.end();
 }
 
 views::AXAuraObjWrapper* AXRootObjWrapper::GetParent() {
   return NULL;
 }
 
 void AXRootObjWrapper::GetChildren(
     std::vector<views::AXAuraObjWrapper*>* out_children) {
-  views::AXAuraObjCache::GetInstance()->GetTopLevelWindows(out_children);
+  if (!ash::Shell::HasInstance())
+    return;
+
+  // Only on ash is there a notion of a root with children.
+  aura::Window::Windows children =
+      ash::Shell::GetInstance()->GetAllRootWindows();
+  for (size_t i = 0; i < children.size(); ++i) {
+    out_children->push_back(
+        views::AXAuraObjCache::GetInstance()->GetOrCreate(children[i]));
+  }
+
+  out_children->push_back(
+      views::AXAuraObjCache::GetInstance()->GetOrCreate(alert_window_));
 }
 
 void AXRootObjWrapper::Serialize(ui::AXNodeData* out_node_data) {
   out_node_data->id = id_;
   out_node_data->role = ui::AX_ROLE_DESKTOP;
   // TODO(dtseng): Apply a richer set of states.
   out_node_data->state = 0;
 }
 
 int32 AXRootObjWrapper::GetID() {
   return id_;
 }