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

chrome/browser/search_engines/template_url_prepopulate_data.cc

Index: chrome/browser/search_engines/template_url_prepopulate_data.cc
diff --git a/chrome/browser/search_engines/template_url_prepopulate_data.cc b/chrome/browser/search_engines/template_url_prepopulate_data.cc
index e4b34bd8e6f2d1dc985f9be09264ca60f5e95f94..389ee9054204b99120b0e2046da2dd6788f7d99c 100644
--- a/chrome/browser/search_engines/template_url_prepopulate_data.cc
+++ b/chrome/browser/search_engines/template_url_prepopulate_data.cc
@@ -1182,12 +1182,15 @@ const PrepopulatedEngine google = {
   "http://www.google.com/favicon.ico",
   L"{google:baseURL}search?{google:RLZ}{google:acceptedSuggestion}"
       L"{google:originalQueryForSuggestion}{google:searchFieldtrialParameter}"
+      L"{google:instantFieldTrialGroupParameter}"
       L"sourceid=chrome&ie={inputEncoding}&q={searchTerms}",
   "UTF-8",
   L"{google:baseSuggestURL}search?{google:searchFieldtrialParameter}"
+      L"{google:instantFieldTrialGroupParameter}"
       L"client=chrome&hl={language}&q={searchTerms}",
-  L"{google:baseURL}webhp?{google:RLZ}sourceid=chrome-instant"
-      L"&ie={inputEncoding}&ion=1{searchTerms}&nord=1",
+  L"{google:baseURL}webhp?{google:RLZ}sourceid=chrome-instant&"
+      L"{google:instantFieldTrialGroupParameter}"
+      L"ie={inputEncoding}&ion=1{searchTerms}&nord=1",
   SEARCH_ENGINE_GOOGLE,
   IDR_SEARCH_ENGINE_LOGO_GOOGLE,
   1,
@@ -3359,7 +3362,7 @@ void RegisterUserPrefs(PrefService* prefs) {
 int GetDataVersion(PrefService* prefs) {
   // Increment this if you change the above data in ways that mean users with
   // existing data should get a new version.
-  const int kCurrentDataVersion = 35;
+  const int kCurrentDataVersion = 36;
   if (!prefs)
     return kCurrentDataVersion;
   // If a version number exist in the preferences file, it overrides the
@@ -3533,7 +3536,7 @@ static GURL GetOriginForSearchURL(const STR& url_string) {
     TemplateURL turl;
     turl.SetURL(url_utf8_string, 0, 0);
 
-    UIThreadSearchTermsData search_terms_data;
+    UIThreadSearchTermsData search_terms_data(NULL);
     url = TemplateURLService::GenerateSearchURLUsingTermsData(
         &turl, search_terms_data);
   }
@@ -3549,7 +3552,6 @@ TemplateURL* GetEngineForOrigin(PrefService* prefs, const GURL& url_to_find) {
   size_t default_search_index;
   GetPrepopulatedEngines(prefs, &loaded_urls.get(), &default_search_index);
 
-  UIThreadSearchTermsData search_terms_data;
   for (std::vector<TemplateURL*>::iterator i = loaded_urls->begin();
        i != loaded_urls->end(); ++i) {
     TemplateURL* template_url = *i;