Refactor ViewsDelegate singleton

ui/views/view.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.
 
 #define _USE_MATH_DEFINES // For VC++ to get M_PI. This has to be first.
 
 #include "ui/views/view.h"
 
 #include <algorithm>
 #include <cmath>
@@ skipping 65 matching lines @@
 const View* GetHierarchyRoot(const View* view) {
   const View* root = view;
   while (root && root->parent())
     root = root->parent();
   return root;
 }
 
 }  // namespace
 
 // static
-ViewsDelegate* ViewsDelegate::views_delegate = NULL;
-
-// static
 const char View::kViewClassName[] = "View";
 
 ////////////////////////////////////////////////////////////////////////////////
 // View, public:
 
 // Creation and lifetime -------------------------------------------------------
 
 View::View()
     : owned_by_client_(false),
       id_(0),
@@ skipping 1177 matching lines @@
   if (!native_view_accessibility_)
     native_view_accessibility_ = NativeViewAccessibility::Create(this);
   if (native_view_accessibility_)
     return native_view_accessibility_->GetNativeObject();
   return NULL;
 }
 
 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_)
       native_view_accessibility_ = NativeViewAccessibility::Create(this);
     if (native_view_accessibility_)
       native_view_accessibility_->NotifyAccessibilityEvent(event_type);
   }
 }
 
 // Scrolling -------------------------------------------------------------------
@@ skipping 1070 matching lines @@
   // Message the RootView to do the drag and drop. That way if we're removed
   // the RootView can detect it and avoid calling us back.
   gfx::Point widget_location(event.location());
   ConvertPointToWidget(this, &widget_location);
   widget->RunShellDrag(this, data, widget_location, drag_operations, source);
   // WARNING: we may have been deleted.
   return true;
 }
 
 }  // namespace views