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

chrome/browser/gtk/gconf_titlebar_listener.h

Index: chrome/browser/gtk/gconf_titlebar_listener.h
diff --git a/chrome/browser/gtk/gconf_titlebar_listener.h b/chrome/browser/gtk/gconf_titlebar_listener.h
index 19318eb8fe91238aaf59a0182b38efaf467f6edf..f8843fd5f88148ef63753948e22e96d6879b7749 100644
--- a/chrome/browser/gtk/gconf_titlebar_listener.h
+++ b/chrome/browser/gtk/gconf_titlebar_listener.h
@@ -24,6 +24,9 @@ class BrowserTitlebar;
 // Meant to be used as a Singleton through base/singleton.h's interface.
 class GConfTitlebarListener {
  public:
+  // Returns the singleton instance.
+  static GConfTitlebarListener* GetInstance();
+
   // Sets the current titlebar button order. On GNOME desktops, also subscribes
   // to further notifications when this changes.
   void SetTitlebarButtons(BrowserTitlebar* titlebar);