Fix Windows XP and Vista taskbar activation issue.

ui/views/widget/native_widget_win.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/widget/native_widget_win.h"
 
 #include <dwmapi.h>
 #include <shellapi.h>
 
 #include <algorithm>
@@ skipping 1694 matching lines @@
                  RDW_NOCHILDREN | RDW_INVALIDATE | RDW_UPDATENOW);
     EnumChildWindows(GetNativeView(), EnumChildWindowsForRedraw, NULL);
   }
 
   // If we're active again, we should be allowed to render as inactive, so
   // tell the non-client view.
   bool inactive_rendering_disabled = delegate_->IsInactiveRenderingDisabled();
   if (IsActive())
     delegate_->EnableInactiveRendering();
 
-  // Avoid DefWindowProc non-client rendering over our custom frame.
-  if (!GetWidget()->ShouldUseNativeFrame()) {
+  // Avoid DefWindowProc non-client rendering over our custom frame on newer
+  // Windows versions only (breaks taskbar activation indication on XP/Vista).
+  if (!GetWidget()->ShouldUseNativeFrame() &&
+      base::win::GetVersion() > base::win::VERSION_VISTA) {
     SetMsgHandled(TRUE);
     return TRUE;
   }
 
   return DefWindowProcWithRedrawLock(
       WM_NCACTIVATE, inactive_rendering_disabled || active, 0);
 }
 
 LRESULT NativeWidgetWin::OnNCCalcSize(BOOL mode, LPARAM l_param) {
   // We only override the default handling if we need to specify a custom
@@ skipping 1032 matching lines @@
 // static
 bool NativeWidgetPrivate::IsTouchDown() {
   // This currently isn't necessary because we're not generating touch events on
   // windows.  When we do, this will need to be updated.
   return false;
 }
 
 }  // namespace internal
 
 }  // namespace views