Put the dropdown menu button on the linux download shelf....

chrome/browser/gtk/nine_box.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_NINE_BOX_H_
 #define CHROME_BROWSER_GTK_NINE_BOX_H_
 
 #include <gdk-pixbuf/gdk-pixbuf.h>
 
 // A NineBox manages a set of source images representing a 3x3 grid, where
 // non-corner images can be tiled to make a larger image.  It's used to
 // use bitmaps for constructing image-based resizable widgets like buttons.
 //
+// If you want just a vertical image that stretches in height but is fixed
+// in width, only pass in images for the left column (leave others NULL).
+// Similarly, for a horizontal image that stretches in width but is fixed in
+// height, only pass in images for the top row.
+//
 // TODO(port): add support for caching server-side pixmaps of prerendered
 // nineboxes.
 class NineBox {
  public:
   // Construct a NineBox with nine images.  NULL images are allowed.
   // Takes ownership of each image, but not the |images| array.
   NineBox(GdkPixbuf* images[9]);
   ~NineBox();
 
   // Render the NineBox to dst.
   // Expects dst to already be the proper size.
   void RenderToPixbuf(GdkPixbuf* dst);
 
   // Render the top row of images to dst between x1 and x2.
   // This is split from RenderToPixbuf so the toolbar can use it.
   void RenderTopCenterStrip(GdkPixbuf* dst, int x1, int x2);
 
  private:
   // Repeatedly stamp src across dst.
   void TileImage(GdkPixbuf* src, GdkPixbuf* dst,
                  int x1, int y1, int x2, int y2);
 
   GdkPixbuf* images_[9];
 };
 
 #endif  // CHROME_BROWSER_GTK_NINE_BOX_H_