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

chrome/app/generated_resources.grd

Index: chrome/app/generated_resources.grd
diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index 277466739fa48d1bc985a24bbbfe2d9fb0d1858b..86face9f544b220fd1c526b1989ffbeda418e8e4 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -8316,6 +8316,10 @@ Keep your key file in a safe place. You will need it to create new versions of y
                desc="Text for the trash can that appears when the user drags apps.">
         Remove from <ph name="SHORT_PRODUCT_NAME">$1<ex>Chrome</ex></ph>.
       </message>
+      <message name="IDS_NEW_TAB_WEBSTORE_PAGE_TITLE"
+         desc="Title for the hard coded thumbnail that represents the webstore page. This is used on the NTP when there aren't enough thumbnails to show.">
+        Apps, Extensions and Themes
+      </message>
       <message name="IDS_APP_DEFAULT_PAGE_NAME"
                desc="Default name for the first 'Apps' page on the New Tab Page.">
         Apps