Add a URL param to indicate group selection in Instant field trial.

chrome/browser/instant/instant_loader.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/instant/instant_loader.h"
 
 #include <algorithm>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 1003 matching lines @@
 
   // Load the instant URL. We don't reflect the url we load in url() as
   // callers expect that we're loading the URL they tell us to.
   //
   // This uses an empty string for the replacement text as the url doesn't
   // really have the search params, but we need to use the replace
   // functionality so that embeded tags (like {google:baseURL}) are escaped
   // correctly.
   // TODO(sky): having to use a replaceable url is a bit of a hack here.
   GURL instant_url(template_url->instant_url()->ReplaceSearchTerms(
-      *template_url, string16(), -1, string16()));
+      tab_contents->profile(), *template_url, string16(), -1, string16()));
   CommandLine* cl = CommandLine::ForCurrentProcess();
   if (cl->HasSwitch(switches::kInstantURL))
     instant_url = GURL(cl->GetSwitchValueASCII(switches::kInstantURL));
   preview_contents_->controller().LoadURL(instant_url, GURL(), transition_type);
   RenderViewHost* host = preview_contents_->render_view_host();
   host->Send(new ViewMsg_SearchBoxChange(
       host->routing_id(), user_text, verbatim, 0, 0));
   frame_load_observer_.reset(new FrameLoadObserver(
       this, preview_contents()->tab_contents(), user_text, verbatim));
 }