Correctly handle extensions width in the GTK extension shelf.

chrome/browser/gtk/extension_view_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_EXTENSION_VIEW_GTK_H_
 #define CHROME_BROWSER_GTK_EXTENSION_VIEW_GTK_H_
 
 #include "base/basictypes.h"
 #include "base/gfx/native_widget_types.h"
 
 class ExtensionHost;
 class RenderViewHost;
 class RenderWidgetHostViewGtk;
 
 class ExtensionViewGtk {
  public:
   explicit ExtensionViewGtk(ExtensionHost* extension_host);
 
   gfx::NativeView native_view();
 
   bool is_toolstrip() const { return is_toolstrip_; }
   void set_is_toolstrip(bool is_toolstrip) { is_toolstrip_ = is_toolstrip; }
 
+  // Method for the ExtensionHost to notify us about the correct width for
+  // extension contents.
+  void UpdatePreferredWidth(int pref_width);
+
  private:
   RenderViewHost* render_view_host() const;
 
   void CreateWidgetHostView();
 
   // True if the contents are being displayed inside the extension shelf.
   bool is_toolstrip_;
 
   ExtensionHost* extension_host_;
 
   RenderWidgetHostViewGtk* render_widget_host_view_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionViewGtk);
 };
 
 #endif  // CHROME_BROWSER_GTK_EXTENSION_VIEW_GTK_H_