[Aura] Fix HtmlDialogBrowserTest.SizeWindow.

ui/aura/window_delegate.h

 // Copyright (c) 2011 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.
 
 #ifndef UI_AURA_WINDOW_DELEGATE_H_
 #define UI_AURA_WINDOW_DELEGATE_H_
 #pragma once
 
 #include "ui/aura/aura_export.h"
 #include "ui/base/events.h"
 #include "ui/gfx/native_widget_types.h"
 
 namespace gfx {
 class Canvas;
 class Point;
 class Rect;
 }
 
 namespace aura {
 
 class Event;
 class KeyEvent;
 class MouseEvent;
 class TouchEvent;
 
 // Delegate interface for aura::Window.
 class AURA_EXPORT WindowDelegate {
  public:
+  // Called before the Window's position and/or size changes and deleage could
+  // take this opportunity to examine and change the new bounds.
+  virtual void OnBoundsChanging(gfx::Rect* new_bounds) = 0;
+
   // Called when the Window's position and/or size changes.
   virtual void OnBoundsChanged(const gfx::Rect& old_bounds,
                                const gfx::Rect& new_bounds) = 0;
 
   // Sent to the Window's delegate when the Window gains or loses focus.
   virtual void OnFocus() = 0;
   virtual void OnBlur() = 0;
 
   virtual bool OnKeyEvent(KeyEvent* event) = 0;
 
@@ skipping 40 matching lines @@
   // Called when the visibility of a Window changed.
   virtual void OnWindowVisibilityChanged(bool visible) = 0;
 
  protected:
   virtual ~WindowDelegate() {}
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_DELEGATE_H_