Revert of Fix icon on Windows XP taskbar

ui/views/win/hwnd_message_handler.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/win/hwnd_message_handler.h"
 
 #include <dwmapi.h>
 #include <oleacc.h>
 #include <shellapi.h>
 #include <wtsapi32.h>
@@ skipping 887 matching lines @@
 
 void HWNDMessageHandler::DispatchKeyEventPostIME(const ui::KeyEvent& key) {
   SetMsgHandled(delegate_->HandleKeyEvent(key));
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // HWNDMessageHandler, gfx::WindowImpl overrides:
 
 HICON HWNDMessageHandler::GetDefaultWindowIcon() const {
   if (use_system_default_icon_)
-    return nullptr;
+    return NULL;
   return ViewsDelegate::views_delegate ?
-      ViewsDelegate::views_delegate->GetDefaultWindowIcon() : nullptr;
-}
-
-HICON HWNDMessageHandler::GetSmallWindowIcon() const {
-  if (use_system_default_icon_)
-    return nullptr;
-  return ViewsDelegate::views_delegate ?
-      ViewsDelegate::views_delegate->GetSmallWindowIcon() : nullptr;
+      ViewsDelegate::views_delegate->GetDefaultWindowIcon() : NULL;
 }
 
 LRESULT HWNDMessageHandler::OnWndProc(UINT message,
                                       WPARAM w_param,
                                       LPARAM l_param) {
   HWND window = hwnd();
   LRESULT result = 0;
 
   if (delegate_ && delegate_->PreHandleMSG(message, w_param, l_param, &result))
     return result;
@@ skipping 1576 matching lines @@
     SetWindowPos(hwnd(), NULL, 0, 0, 0, 0, flags | SWP_HIDEWINDOW);
     SetWindowPos(hwnd(), NULL, 0, 0, 0, 0, flags | SWP_SHOWWINDOW);
   }
   // WM_DWMCOMPOSITIONCHANGED is only sent to top level windows, however we want
   // to notify our children too, since we can have MDI child windows who need to
   // update their appearance.
   EnumChildWindows(hwnd(), &SendDwmCompositionChanged, NULL);
 }
 
 }  // namespace views