Add a new GetInstance() method for remaining files with singleton classes under chrome/browser.

chrome/browser/gtk/gconf_titlebar_listener.cc

Index: chrome/browser/gtk/gconf_titlebar_listener.cc
diff --git a/chrome/browser/gtk/gconf_titlebar_listener.cc b/chrome/browser/gtk/gconf_titlebar_listener.cc
index 237332fdbb4945720cc2e9cb7b618b34f109eed2..0d37b08a6fd914a334c69b4886e801c42f530c95 100644
--- a/chrome/browser/gtk/gconf_titlebar_listener.cc
+++ b/chrome/browser/gtk/gconf_titlebar_listener.cc
@@ -25,6 +25,11 @@ const char* kMetacityGeneral = "/apps/metacity/general";
 
 // Public interface:
 
+// static
+GConfTitlebarListener* GConfTitlebarListener::GetInstance() {
+  return Singleton<GConfTitlebarListener>::get();
+}
+
 void GConfTitlebarListener::SetTitlebarButtons(BrowserTitlebar* titlebar) {
   if (client_) {
     titlebar->BuildButtons(current_value_);