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

chrome/browser/autocomplete/keyword_provider.h

Index: chrome/browser/autocomplete/keyword_provider.h
diff --git a/chrome/browser/autocomplete/keyword_provider.h b/chrome/browser/autocomplete/keyword_provider.h
index 612be6957dd9ce3c1c2d92c3f51c0a7f8c5775a1..fdc6ae2ef2f4eca559c0b6687c940e5a297c18c7 100644
--- a/chrome/browser/autocomplete/keyword_provider.h
+++ b/chrome/browser/autocomplete/keyword_provider.h
@@ -104,6 +104,7 @@ class KeywordProvider : public AutocompleteProvider,
   // Fills in the "destination_url" and "contents" fields of |match| with the
   // provided user input and keyword data.
   static void FillInURLAndContents(
+      Profile* profile,
       const string16& remaining_input,
       const TemplateURL* element,
       AutocompleteMatch* match);