GTK: First draft of using native themes, partially based on evan's CL 118358.

chrome/browser/gtk/bookmark_bar_gtk.h

Index: chrome/browser/gtk/bookmark_bar_gtk.h
diff --git a/chrome/browser/gtk/bookmark_bar_gtk.h b/chrome/browser/gtk/bookmark_bar_gtk.h
index d7f5eb8ff4a47556a87f28f375875762a18a3a03..3d0c03cc17b28b34435ae816372f3419b50a04bb 100644
--- a/chrome/browser/gtk/bookmark_bar_gtk.h
+++ b/chrome/browser/gtk/bookmark_bar_gtk.h
@@ -67,6 +67,9 @@ class BookmarkBarGtk : public AnimationDelegate,
   // Returns true if the bookmarks bar preference is set to 'always show'.
   bool IsAlwaysShown();
 
+  // Alerts us that the theme changed, and we might need to change theme images.
+  void UserChangedTheme(Profile* profile);
+
   // AnimationDelegate implementation ------------------------------------------
   virtual void AnimationProgressed(const Animation* animation);
   virtual void AnimationEnded(const Animation* animation);