Make the dismiss button on the CF infobar be an image button.

chrome_frame/resources/chrome_frame_resources.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
-<!-- 
+<!--
 Copyright (c) 2010 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.
 -->
 
 <!--
-Embeded strings, branding resource, etc. See chrome_frame_strings.grd 
+Embeded strings, branding resource, etc. See chrome_frame_strings.grd
 for localizable strings
 -->
 
 <grit latest_public_release="0" current_release="1">
   <outputs>
     <output filename="grit/chrome_frame_resources.h" type="rc_header">
       <emit emit_type='prepend'></emit>
     </output>
     <output filename="chrome_frame_resources.pak" type="data_package" />
     <output filename="chrome_frame_resources.rc" type="rc_all" lang="en"/>
@@ skipping 11 matching lines @@
       <include name="IDR_CHROMEFRAME_ELEVATION" file="../chrome_frame_elevation.rgs" type="REGISTRY" />
       <include name="IDR_CHROMEFRAME_NPAPI" file="../chrome_frame_npapi.rgs" type="REGISTRY" />
       <include name="IDR_CHROMEPROTOCOL" file="../chrome_protocol.rgs" type="REGISTRY" />
       <include name="IDR_CHROMETAB" file="../chrome_tab.rgs" type="REGISTRY" />
       <if expr="pp_ifdef('_google_chrome')">
         <include name="IDI_CHROME_FRAME_ICON" file="../../chrome/app/theme/google_chrome/chrome.ico" type="ICON" />
       </if>
       <if expr="not pp_ifdef('_google_chrome')">
         <include name="IDI_CHROME_FRAME_ICON" file="../../chrome/app/theme/chromium/chromium.ico" type="ICON" />
       </if>
+      <include name="IDB_TURNDOWN_PROMPT_CLOSE_BUTTON" file="../../chrome/app/theme/default_100_percent/common/cf_close_strip.bmp" type="BITMAP" />
     </includes>
   </release>
 </grit>