The updated (simplified) look of set-as-default dialog on Windows8.

chrome/app/resources/locale_settings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 <grit latest_public_release="0" current_release="1">
   <outputs>
     <output filename="grit/locale_settings.h" type="rc_header">
       <emit emit_type='prepend'></emit>
     </output>
     <output filename="locale_settings_am.pak" type="data_package" lang="am" />
     <output filename="locale_settings_ar.pak" type="data_package" lang="ar" />
     <if expr="pp_ifdef('use_third_party_translations')">
       <output filename="locale_settings_ast.pak" type="data_package" lang="ast" />
@@ skipping 416 matching lines @@
         </message>
       </if>
 
       <!-- The width of the Instant confirm dialog box in characters. -->
       <message name="IDS_INSTANT_CONFIRM_DIALOG_WIDTH_CHARS" use_name_for_id="true">
         70
       </message>
       
       <!-- The width of the make-default-in-metro dialog in characters. -->
       <message name="IDS_METRO_FLOW_WIDTH_CHARS" use_name_for_id="true">
-        72
+        78
       </message>
 
       <!-- The height of the make-default-in-metro dialog in characters. -->
       <message name="IDS_METRO_FLOW_HEIGHT_LINES" use_name_for_id="true">
         26
       </message>
 
       <if expr="pp_ifdef('chromeos')">
         <!-- The width and height of the CAPTCHA challenge dialog box in -->
         <!-- characters and lines (See above). -->
         <message name="IDS_CAPTCHA_INPUT_DIALOG_WIDTH_CHARS" use_name_for_id="true">
           60
         </message>
         <message name="IDS_CAPTCHA_INPUT_DIALOG_HEIGHT_LINES" use_name_for_id="true">
           13
         </message>
 
         <!-- The width and height of the password changed dialog box in -->
         <!-- characters and lines (See above). -->
         <message name="IDS_PASSWORD_CHANGED_DIALOG_WIDTH_CHARS" use_name_for_id="true">
           70
         </message>
         <message name="IDS_PASSWORD_CHANGED_DIALOG_HEIGHT_LINES" use_name_for_id="true">
           16
         </message>
       </if>
     </messages>
   </release>
 </grit>