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

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

Index: chrome/browser/ui/ash/accessibility/ax_root_obj_wrapper.cc
diff --git a/chrome/browser/ui/aura/accessibility/ax_root_obj_wrapper.cc b/chrome/browser/ui/ash/accessibility/ax_root_obj_wrapper.cc
similarity index 75%
rename from chrome/browser/ui/aura/accessibility/ax_root_obj_wrapper.cc
rename to chrome/browser/ui/ash/accessibility/ax_root_obj_wrapper.cc
index b565bde99088d7a7f3fb4270cff2ed8dd3fd296b..366955d1a355431b1b4b6938a22822c83f22369b 100644
--- a/chrome/browser/ui/aura/accessibility/ax_root_obj_wrapper.cc
+++ b/chrome/browser/ui/ash/accessibility/ax_root_obj_wrapper.cc
@@ -2,8 +2,9 @@
 // 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"
@@ -44,7 +45,19 @@ views::AXAuraObjWrapper* AXRootObjWrapper::GetParent() {
 
 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) {