Fix accessibility in Windows x64 build.

ui/views/accessibility/native_view_accessibility_win.cc

Index: ui/views/accessibility/native_view_accessibility_win.cc
diff --git a/ui/views/accessibility/native_view_accessibility_win.cc b/ui/views/accessibility/native_view_accessibility_win.cc
index 241087d84f54fc19ac0b7e2891cd6715b90da306..466c296c105d5f70458d144bf5ad604e35d76ce5 100644
--- a/ui/views/accessibility/native_view_accessibility_win.cc
+++ b/ui/views/accessibility/native_view_accessibility_win.cc
@@ -30,6 +30,9 @@
 namespace views {
 namespace {
 
+// A version of the OBJID_CLIENT constant that works in 64-bit mode too.
+static const LPARAM kObjIdClient = static_cast<ULONG>(OBJID_CLIENT);
+
 class AccessibleWebViewRegistry {
  public:
   static AccessibleWebViewRegistry* GetInstance();
@@ -787,9 +790,9 @@ STDMETHODIMP NativeViewAccessibilityWin::accSelect(
 
 STDMETHODIMP NativeViewAccessibilityWin::get_accHelp(
     VARIANT var_id, BSTR* help) {
-  if (help)
-    *help = NULL;
-  return E_NOTIMPL;
+  base::string16 temp = base::UTF8ToUTF16(view_->GetClassName());
+  *help = SysAllocString(temp.c_str());
+  return S_OK;
 }
 
 STDMETHODIMP NativeViewAccessibilityWin::get_accHelpTopic(