Refactor ViewsDelegate singleton

ui/views/controls/textfield/textfield.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 "ui/views/controls/textfield/textfield.h"
 
 #include <string>
 
 #include "base/trace_event/trace_event.h"
 #include "ui/accessibility/ax_view_state.h"
@@ skipping 266 matching lines @@
       initiating_drag_(false),
       aggregated_clicks_(0),
       drag_start_display_offset_(0),
       touch_handles_hidden_due_to_scroll_(false),
       weak_ptr_factory_(this) {
   set_context_menu_controller(this);
   set_drag_controller(this);
   SetBorder(scoped_ptr<Border>(new FocusableBorder()));
   SetFocusable(true);
 
-  if (ViewsDelegate::views_delegate) {
-    password_reveal_duration_ = ViewsDelegate::views_delegate->
-        GetDefaultTextfieldObscuredRevealDuration();
+  if (ViewsDelegate::GetInstance()) {
+    password_reveal_duration_ =
+        ViewsDelegate::GetInstance()
+            ->GetDefaultTextfieldObscuredRevealDuration();
   }
 }
 
 Textfield::~Textfield() {}
 
 void Textfield::SetReadOnly(bool read_only) {
   // Update read-only without changing the focusable state (or active, etc.).
   read_only_ = read_only;
   if (GetInputMethod())
     GetInputMethod()->OnTextInputTypeChanged(this);
@@ skipping 1598 matching lines @@
     RequestFocus();
   model_->MoveCursorTo(mouse);
   if (!selection_clipboard_text.empty()) {
     model_->InsertText(selection_clipboard_text);
     UpdateAfterChange(true, true);
   }
   OnAfterUserAction();
 }
 
 }  // namespace views