Fix race in BrowserAccessibilityManagerWin creation.

content/browser/accessibility/browser_accessibility_win.cc

 // Copyright (c) 2012 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 "content/browser/accessibility/browser_accessibility_win.h"
 
 #include <UIAutomationClient.h>
 #include <UIAutomationCoreApi.h>
 
 #include "base/strings/string_number_conversions.h"
@@ skipping 721 matching lines @@
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_windowHandle(HWND* window_handle) {
   if (!instance_active())
     return E_FAIL;
 
   if (!window_handle)
     return E_INVALIDARG;
 
   *window_handle = manager()->ToBrowserAccessibilityManagerWin()->parent_hwnd();
+  if (!*window_handle)
+    return E_FAIL;
+
   return S_OK;
 }
 
 STDMETHODIMP BrowserAccessibilityWin::get_indexInParent(LONG* index_in_parent) {
   if (!instance_active())
     return E_FAIL;
 
   if (!index_in_parent)
     return E_INVALIDARG;
 
@@ skipping 233 matching lines @@
     LONG* y) {
   if (!instance_active())
     return E_FAIL;
 
   if (!x || !y)
     return E_INVALIDARG;
 
   if (coordinate_type == IA2_COORDTYPE_SCREEN_RELATIVE) {
     HWND parent_hwnd =
         manager()->ToBrowserAccessibilityManagerWin()->parent_hwnd();
+    if (!parent_hwnd)
+      return E_FAIL;
     POINT top_left = {0, 0};
     ::ClientToScreen(parent_hwnd, &top_left);
     *x = GetLocation().x() + top_left.x;
     *y = GetLocation().y() + top_left.y;
   } else if (coordinate_type == IA2_COORDTYPE_PARENT_RELATIVE) {
     *x = GetLocation().x();
     *y = GetLocation().y();
     if (GetParent()) {
       *x -= GetParent()->GetLocation().x();
       *y -= GetParent()->GetLocation().y();
@@ skipping 2779 matching lines @@
   // The role should always be set.
   DCHECK(!role_name_.empty() || ia_role_);
 
   // If we didn't explicitly set the IAccessible2 role, make it the same
   // as the MSAA role.
   if (!ia2_role_)
     ia2_role_ = ia_role_;
 }
 
 }  // namespace content