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..56cb77aaf5de0fb200b9c7b1ecd9783cbedb65f0 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