Make WindowImpl take into account the icon in the class registrar.

ui/base/win/window_impl.h

 // 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.
 
 #ifndef UI_BASE_WIN_WINDOW_IMPL_H_
 #define UI_BASE_WIN_WINDOW_IMPL_H_
 #pragma once
 
 #include <atlbase.h>
 #include <atlapp.h>
@@ skipping 31 matching lines @@
 //
 ///////////////////////////////////////////////////////////////////////////////
 class UI_EXPORT WindowImpl : public MessageMapInterface {
  public:
   WindowImpl();
   virtual ~WindowImpl();
 
   // Initializes the Window with a parent and an initial desired size.
   void Init(HWND parent, const gfx::Rect& bounds);
 
-  // Retrieves the default window icon to use for windows if none is specified.
+  // Returns the default window icon to use for windows of this type.
   virtual HICON GetDefaultWindowIcon() const;
 
   // Returns the HWND associated with this Window.
   HWND hwnd() const { return hwnd_; }
 
   // Sets the window styles. This is ONLY used when the window is created.
   // In other words, if you invoke this after invoking Init, nothing happens.
   void set_window_style(DWORD style) { window_style_ = style; }
   DWORD window_style() const { return window_style_; }
 
@@ skipping 46 matching lines @@
   bool got_create_;
   bool got_valid_hwnd_;
   bool* destroyed_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowImpl);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_WIN_WINDOW_IMPL_H_