Fix race in BrowserAccessibilityManagerWin creation.

content/browser/accessibility/browser_accessibility_win.cc

Index: content/browser/accessibility/browser_accessibility_win.cc
diff --git a/content/browser/accessibility/browser_accessibility_win.cc b/content/browser/accessibility/browser_accessibility_win.cc
index e98ae71498b4dde47494c28b7803ffe67476adbe..58435d15b2bbe8446f96876c898a0be4ffd60e44 100644
--- a/content/browser/accessibility/browser_accessibility_win.cc
+++ b/content/browser/accessibility/browser_accessibility_win.cc
@@ -497,8 +497,8 @@ STDMETHODIMP BrowserAccessibilityWin::get_accParent(IDispatch** disp_parent) {
   if (parent_obj == NULL) {
     // This happens if we're the root of the tree;
     // return the IAccessible for the window.
-    parent_obj =
-         manager()->ToBrowserAccessibilityManagerWin()->parent_iaccessible();
+    if (manager()->delegate())
+      parent_obj = manager()->delegate()->GetParentIAccessible();
     // |parent| can only be NULL if the manager was created before the parent
     // IAccessible was known and it wasn't subsequently set before a client
     // requested it. This has been fixed. |parent| may also be NULL during
@@ -738,7 +738,10 @@ STDMETHODIMP BrowserAccessibilityWin::get_windowHandle(HWND* window_handle) {
   if (!window_handle)
     return E_INVALIDARG;
 
-  *window_handle = manager()->ToBrowserAccessibilityManagerWin()->parent_hwnd();
+  if (!manager()->delegate())
+    return E_FAIL;
+
+  *window_handle = manager()->delegate()->GetAccessibleParentHWND();
   return S_OK;
 }
 
@@ -990,8 +993,9 @@ STDMETHODIMP BrowserAccessibilityWin::get_imagePosition(
     return E_INVALIDARG;
 
   if (coordinate_type == IA2_COORDTYPE_SCREEN_RELATIVE) {
-    HWND parent_hwnd =
-        manager()->ToBrowserAccessibilityManagerWin()->parent_hwnd();
+    if (!manager()->delegate())
+      return E_FAIL;
+    HWND parent_hwnd = manager()->delegate()->GetAccessibleParentHWND();
     POINT top_left = {0, 0};
     ::ClientToScreen(parent_hwnd, &top_left);
     *x = GetLocation().x() + top_left.x;