Gtk3: Render a GtkHeaderBar as the background of the tab strip

chrome/browser/ui/libgtkui/gtk_util.h

Index: chrome/browser/ui/libgtkui/gtk_util.h
diff --git a/chrome/browser/ui/libgtkui/gtk_util.h b/chrome/browser/ui/libgtkui/gtk_util.h
index 4e722a4cb276f98e2a08f326366e0cd24227f586..b396377d1b7e4cbc62db41850790a014b0b759d4 100644
--- a/chrome/browser/ui/libgtkui/gtk_util.h
+++ b/chrome/browser/ui/libgtkui/gtk_util.h
@@ -120,6 +120,9 @@ typedef ScopedGObject<GtkStyleContext> ScopedStyleContext;
 // must g_object_unref() the returned context.
 ScopedStyleContext GetStyleContextFromCss(const char* css_selector);
 
+// Removes all border-type properties on |context| and all of its parents.
+void RemoveBorders(GtkStyleContext* context);
+
 // Get the 'color' property from the style context created by
 // GetStyleContextFromCss(|css_selector|).
 SkColor GetFgColor(const char* css_selector);