Hide the browser actions gripper when it's not in use.

chrome/browser/gtk/browser_actions_toolbar_gtk.h

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_GTK_BROWSER_ACTIONS_TOOLBAR_GTK_H_
 #define CHROME_BROWSER_GTK_BROWSER_ACTIONS_TOOLBAR_GTK_H_
 
 #include <gtk/gtk.h>
 
 #include <map>
@@ skipping 177 matching lines @@
       ExtensionButtonMap;
   ExtensionButtonMap extension_button_map_;
 
   // We use this animation for the smart resizing of the toolbar.
   SlideAnimation resize_animation_;
   // This is the final width we are animating towards.
   int desired_width_;
   // This is the width we were at when we started animating.
   int start_width_;
 
+  // We only draw the browser action gripper when the user is hovering over it
+  // or dragging it.
+  bool draw_gripper_;
+
   GtkSignalRegistrar signals_;
 
   ScopedRunnableMethodFactory<BrowserActionsToolbarGtk> method_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BrowserActionsToolbarGtk);
 };
 
 #endif  // CHROME_BROWSER_GTK_BROWSER_ACTIONS_TOOLBAR_GTK_H_