views: Make view::Views::GetPreferredSize() const.

ash/system/chromeos/virtual_keyboard/virtual_keyboard_tray.cc

 // Copyright 2014 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 "ash/system/chromeos/virtual_keyboard/virtual_keyboard_tray.h"
 
 #include "ash/shelf/shelf_constants.h"
 #include "ash/shell.h"
 #include "ash/system/status_area_widget.h"
 #include "ash/system/tray/system_tray_notifier.h"
@@ skipping 10 matching lines @@
 
 namespace ash {
 namespace {
 
 class VirtualKeyboardButton : public views::ImageButton {
  public:
   VirtualKeyboardButton(views::ButtonListener* listener);
   virtual ~VirtualKeyboardButton();
 
   // Overridden from views::ImageButton:
-  virtual gfx::Size GetPreferredSize() OVERRIDE;
+  virtual gfx::Size GetPreferredSize() const OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(VirtualKeyboardButton);
 };
 
 VirtualKeyboardButton::VirtualKeyboardButton(views::ButtonListener* listener)
     : views::ImageButton(listener) {
 }
 
 VirtualKeyboardButton::~VirtualKeyboardButton() {
 }
 
-gfx::Size VirtualKeyboardButton::GetPreferredSize() {
+gfx::Size VirtualKeyboardButton::GetPreferredSize() const {
   const int virtual_keyboard_button_height = kShelfSize;
   gfx::Size size = ImageButton::GetPreferredSize();
   int padding = virtual_keyboard_button_height - size.height();
   size.set_height(virtual_keyboard_button_height);
   size.set_width(size.width() + padding);
   return size;
 }
 
 }  // namespace
 
@@ skipping 54 matching lines @@
   PerformAction(event);
 }
 
 void VirtualKeyboardTray::OnAccessibilityModeChanged(
     AccessibilityNotificationVisibility notify) {
   SetVisible(Shell::GetInstance()->accessibility_delegate()->
       IsVirtualKeyboardEnabled());
 }
 
 }  // namespace ash