NewTabPage: Remove impression/click ping plumbing for local NTP

chrome/common/search/instant_types.h

Index: chrome/common/search/instant_types.h
diff --git a/chrome/common/search/instant_types.h b/chrome/common/search/instant_types.h
index 8d78eab78cccfae2f613089ccd5e0d8c3d1fd084..7c7afa84f924270e9a4744a27f1dce1a8bce469b 100644
--- a/chrome/common/search/instant_types.h
+++ b/chrome/common/search/instant_types.h
@@ -141,10 +141,6 @@ struct InstantMostVisitedItem {
   // The external URL of the favicon associated with this page.
   GURL favicon;
 
-  // The external URL that should be pinged when this item is suggested/clicked.
-  GURL impression_url;
-  GURL click_url;
-
   // True if it's a server side suggestion.
   // Otherwise, it's a client side suggestion.
   bool is_server_side_suggestion;