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

chrome/browser/autocomplete/search_provider.cc

Index: chrome/browser/autocomplete/search_provider.cc
diff --git a/chrome/browser/autocomplete/search_provider.cc b/chrome/browser/autocomplete/search_provider.cc
index 2bbda0bb2b06a35660046f72c1cd8f65b6866d67..f36402fd81ace8acbf66eb431b21eb73c4f137c0 100644
--- a/chrome/browser/autocomplete/search_provider.cc
+++ b/chrome/browser/autocomplete/search_provider.cc
@@ -441,7 +441,7 @@ URLFetcher* SearchProvider::CreateSuggestFetcher(int id,
   DCHECK(suggestions_url->SupportsReplacement());
   URLFetcher* fetcher = URLFetcher::Create(id,
       GURL(suggestions_url->ReplaceSearchTerms(
-           provider, text,
+           profile_, provider, text,
            TemplateURLRef::NO_SUGGESTIONS_AVAILABLE, string16())),
       URLFetcher::GET, this);
   fetcher->set_request_context(profile_->GetRequestContext());
@@ -884,7 +884,8 @@ void SearchProvider::AddMatchToMap(const string16& query_string,
   const TemplateURLRef* const search_url = provider.url();
   DCHECK(search_url->SupportsReplacement());
   match.destination_url =
-      GURL(search_url->ReplaceSearchTerms(provider,
+      GURL(search_url->ReplaceSearchTerms(profile_,
+                                          provider,
                                           query_string,
                                           accepted_suggestion,
                                           input_text));