Refactor ViewsDelegate singleton

ui/views/view.cc

Index: ui/views/view.cc
diff --git a/ui/views/view.cc b/ui/views/view.cc
index 0b6efdf1086b52cf535a4b253d5fb92f70749d9c..420f5da6e20295250092a6c39a4481e51eecc4be 100644
--- a/ui/views/view.cc
+++ b/ui/views/view.cc
@@ -83,9 +83,6 @@ const View* GetHierarchyRoot(const View* view) {
 }  // namespace
 
 // static
-ViewsDelegate* ViewsDelegate::views_delegate = NULL;
-
-// static
 const char View::kViewClassName[] = "View";
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -1283,8 +1280,8 @@ gfx::NativeViewAccessible View::GetNativeViewAccessible() {
 void View::NotifyAccessibilityEvent(
     ui::AXEvent event_type,
     bool send_native_event) {
-  if (ViewsDelegate::views_delegate)
-    ViewsDelegate::views_delegate->NotifyAccessibilityEvent(this, event_type);
+  if (ViewsDelegate::GetInstance())
+    ViewsDelegate::GetInstance()->NotifyAccessibilityEvent(this, event_type);
 
   if (send_native_event && GetWidget()) {
     if (!native_view_accessibility_)