Fixes crash with instant enabled. The crash would occur if you turned

chrome/browser/instant/instant_controller.cc

 // Copyright (c) 2011 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/instant/instant_controller.h"
 
 #include "base/command_line.h"
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "build/build_config.h"
@@ skipping 352 matching lines @@
     return;
 
   if (is_active_)
     return;
 
   TemplateURLModel* model = tab_contents->profile()->GetTemplateURLModel();
   if (!model)
     return;
 
   const TemplateURL* template_url = model->GetDefaultSearchProvider();
-  if (!template_url)
+  if (!template_url || !template_url->instant_url())
     return;
 
   if (tab_contents != tab_contents_)
     DestroyPreviewContents();
   tab_contents_ = tab_contents;
 
   if (!loader_manager_.get())
     loader_manager_.reset(new InstantLoaderManager(this));
   loader_manager_->GetInstantLoader(template_url->id())
                  ->MaybeLoadInstantURL(tab_contents, template_url);
@@ skipping 342 matching lines @@
     const AutocompleteMatch& match) {
   const TemplateURL* template_url = match.template_url;
   if (match.type == AutocompleteMatch::SEARCH_WHAT_YOU_TYPED ||
       match.type == AutocompleteMatch::SEARCH_HISTORY ||
       match.type == AutocompleteMatch::SEARCH_SUGGEST) {
     TemplateURLModel* model = tab_contents_->profile()->GetTemplateURLModel();
     template_url = model ? model->GetDefaultSearchProvider() : NULL;
   }
   return template_url;
 }