Correctly handle extensions width in the GTK extension shelf.

chrome/browser/gtk/extension_view_gtk.cc

 // 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.
 
 #include "chrome/browser/gtk/extension_view_gtk.h"
 
 #include "chrome/browser/extensions/extension_host.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/renderer_host/render_widget_host_view_gtk.h"
 
 ExtensionViewGtk::ExtensionViewGtk(ExtensionHost* extension_host)
     : is_toolstrip_(true),
       extension_host_(extension_host),
       render_widget_host_view_(NULL) {
   CreateWidgetHostView();
 }
 
 gfx::NativeView ExtensionViewGtk::native_view() {
   return render_widget_host_view_->native_view();
 }
 
 RenderViewHost* ExtensionViewGtk::render_view_host() const {
   return extension_host_->render_view_host();
 }
 
+void ExtensionViewGtk::UpdatePreferredWidth(int pref_width) {
+  gtk_widget_set_size_request(native_view(), pref_width, -1);
+}
+
 void ExtensionViewGtk::CreateWidgetHostView() {
   DCHECK(!render_widget_host_view_);
   render_widget_host_view_ = new RenderWidgetHostViewGtk(render_view_host());
   render_widget_host_view_->InitAsChild();
 
   extension_host_->CreateRenderView(render_widget_host_view_);
 }