InstantExtended: add back focus() API call.

chrome/renderer/searchbox/searchbox.cc

Index: chrome/renderer/searchbox/searchbox.cc
diff --git a/chrome/renderer/searchbox/searchbox.cc b/chrome/renderer/searchbox/searchbox.cc
index 8130cd0b1ca71de7496435bb463acbdb08a72150..be0f880e7b81b455fac4f8ec9669051bfc63c953 100644
--- a/chrome/renderer/searchbox/searchbox.cc
+++ b/chrome/renderer/searchbox/searchbox.cc
@@ -223,6 +223,12 @@ const ThemeBackgroundInfo& SearchBox::GetThemeBackgroundInfo() {
   return theme_info_;
 }
 
+void SearchBox::Focus() {
+  render_view()->Send(new ChromeViewHostMsg_FocusOmnibox(
+      render_view()->GetRoutingID(), render_view()->GetPageId(),
+      OMNIBOX_FOCUS_VISIBLE));
+}
+
 void SearchBox::NavigateToURL(const GURL& url,
                               content::PageTransition transition,
                               WindowOpenDisposition disposition,