ntp: use web store as default mv tile instead of themes gallery

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 324 matching lines @@
       <message name="IDS_FIRSTRUN_DLG_OK" desc="Text for OK button on first-run dialog">
         Start Chromium
       </message>
       <message name="IDS_FR_CUSTOMIZE_DEFAULT_BROWSER" desc="Default browser checkbox label">
         Make Chromium the default browser
       </message>
       <message name="IDS_NEW_TAB_CHROME_WELCOME_PAGE_TITLE"
                desc="Title for the hard-coded thumbnail that represents the Google Chrome Welcome page.  This is used on the NTP when there aren't enough thumbnails to show.">
         Welcome to Chromium
       </message>
-      <message name="IDS_NEW_TAB_THEMES_GALLERY_PAGE_TITLE"
-         desc="Title for the hard coded thumbnail that represents the Themes Gallery page. This is used on the NTP when there aren't enough thumbnails to show.">
-        Chromium Themes Gallery
-      </message>
       <if expr="not pp_ifdef('chromeos')">
         <message name="IDS_EXTERNAL_PROTOCOL_INFORMATION" desc="General information about what Chrome is trying to do when opening this external protocol">
           Chromium needs to launch an external application to handle <ph name="SCHEME">$1<ex>acrobat:</ex></ph> links. The link requested is <ph name="PROTOLINK">$2<ex>acrobat:yourpdf</ex></ph>.
         </message>
       </if>
       <if expr="pp_ifdef('chromeos')">
         <message name="IDS_EXTERNAL_PROTOCOL_INFORMATION" desc="General information about what Chrome is trying to do when opening this external protocol">
           Chromium OS does not support launching an external application to handle <ph name="SCHEME">$1<ex>acrobat:</ex></ph> links. The link requested is <ph name="PROTOLINK">$2<ex>acrobat:yourpdf</ex></ph>.
         </message>
       </if>
@@ skipping 238 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>