Return a new error code for multi-install updates if Group Policy settings blocking...

chrome/app/chromium_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 <!-- This file contains definitions of strings that are distribution specific.
 These strings will not be translated and only english versions will
 be available for now. -->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       source_lang_id="en" enc_check="möl">
   <outputs>
     <output filename="grit/chromium_strings.h" type="rc_header">
       <emit emit_type='prepend'></emit>
@@ skipping 449 matching lines @@
       </message>
       <message name="IDS_INSTALL_MULTI_INSTALLATION_EXISTS" desc="Error during install if a multi-install Chromium or Chromium Frame is present, thereby preventing the installation of a single-install Chromium or Chromium Frame.">
         A conflicting installation of Chromium or Chromium Frame was found on the system. Please uninstall it and try again.
       </message>
       <message name="IDS_INSTALL_CONFLICTING_CHANNEL_EXISTS" desc="Error during install if a version of Chromium on a different update channel exists when installing Chromium Frame.">
         A conflicting installation of Chromium was found on the system. Please uninstall it and try again.
       </message>
       <message name="IDS_INSTALL_READY_MODE_REQUIRES_CHROME" desc="Chrome Frame in ready mode requires Chrome.">
         Invalid arguments. Chromium Frame cannot be installed in ready mode without also installing Chromium.
       </message>
+      <message name="IDS_INSTALL_INCONSISTENT_UPDATE_POLICY" desc="This message does not apply to Chromium.">
+      </message>
       <!-- Options Dialog -->
       <message name="IDS_OPTIONS_IMPROVE_BROWSING_EXPERIENCE" desc="The text in the options panel that describes how we use web services to improve browsing experience.">
         Chromium may use web services to improve your browsing experience.
       </message>
       <message name="IDS_IMPORT_BOOKMARKS" desc="Explanatory text for the importing progress dialog when importing a bookmarks.html file from the bookmark manager">
         Chromium is now importing Favorites/Bookmarks.
       </message>
       <message name="IDS_OEM_MAIN_SHORTCUT_NAME" desc="Name of the desktop shortcut to start the application for OEM pre-installations.">
         Internet Browser
       </message>
@@ skipping 96 matching lines @@
         <message name="IDS_UTILITY_APP_NAME" desc="The utility application's name.  Should contain the Chrome application name (IDS_PRODUCT_NAME). Example: Google Chrome Utility.">
           Chromium Utility
         </message>
         <message name="IDS_SHORT_UTILITY_APP_NAME" desc="The utility application's short name, used for the Mac's application menu, activity monitor, etc. Example: Chrome Utility, not Google Chrome Utility.">
           Chromium Utility
         </message>
       </if>
     </messages>
   </release>
 </grit>