LabelButton: cache the last computed preferred size

ui/views/button_drag_utils.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/button_drag_utils.h"
 
 #include "base/strings/utf_string_conversions.h"
 #include "grit/ui_resources.h"
 #include "ui/base/dragdrop/drag_utils.h"
 #include "ui/base/dragdrop/os_exchange_data.h"
@@ skipping 33 matching lines @@
                             title.empty() ? base::UTF8ToUTF16(url.spec())
                                           : title);
   button.SetTextSubpixelRenderingEnabled(false);
   const ui::NativeTheme* theme =
       widget ? widget->GetNativeTheme() : ui::NativeTheme::instance();
   button.SetTextColor(views::Button::STATE_NORMAL,
       theme->GetSystemColor(ui::NativeTheme::kColorId_LabelEnabledColor));
   gfx::ShadowValues shadows(10, gfx::ShadowValue(gfx::Point(0,0), 1.0f,
       theme->GetSystemColor(ui::NativeTheme::kColorId_LabelBackgroundColor)));
   button.SetTextShadows(shadows);
-  button.set_max_size(gfx::Size(kLinkDragImageMaxWidth, 0));
+  button.SetMaxSize(gfx::Size(kLinkDragImageMaxWidth, 0));
   if (icon.isNull()) {
     button.SetImage(views::Button::STATE_NORMAL,
                     *ui::ResourceBundle::GetSharedInstance().GetImageNamed(
                         IDR_DEFAULT_FAVICON).ToImageSkia());
   } else {
     button.SetImage(views::Button::STATE_NORMAL, icon);
   }
   gfx::Size prefsize = button.GetPreferredSize();
   button.SetBounds(0, 0, prefsize.width(), prefsize.height());
 
   gfx::Vector2d press_point;
   if (press_pt)
     press_point = press_pt->OffsetFromOrigin();
   else
     press_point = gfx::Vector2d(prefsize.width() / 2, prefsize.height() / 2);
 
   // Render the image.
   scoped_ptr<gfx::Canvas> canvas(
       views::GetCanvasForDragImage(widget, prefsize));
   button.Paint(canvas.get(), views::CullSet());
   drag_utils::SetDragImageOnDataObject(*canvas, press_point, data);
 }
 
 }  // namespace button_drag_utils