Makes the current page dim out when transitioning to instant preview.

chrome/browser/instant/instant_controller.cc

 // Copyright (c) 2010 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 "chrome/browser/autocomplete/autocomplete_match.h"
 #include "chrome/browser/instant/instant_delegate.h"
 #include "chrome/browser/instant/instant_loader.h"
@@ skipping 75 matching lines @@
     DestroyPreviewContents();
     return;
   }
 
   const TemplateURL* template_url = GetTemplateURL(match);
   TemplateURLID template_url_id = template_url ? template_url->id() : 0;
 
   if (!loader_manager_.get())
     loader_manager_.reset(new InstantLoaderManager(this));
 
+  if (!is_active_)
+    delegate_->PrepareForInstant();
+
   if (ShouldUpdateNow(template_url_id, match.destination_url)) {
     UpdateLoader(template_url, match.destination_url, match.transition,
                  user_text, suggested_text);
   } else {
     ScheduleUpdate(match.destination_url);
   }
 
   NotificationService::current()->Notify(
       NotificationType::INSTANT_CONTROLLER_UPDATED,
       Source<InstantController>(this),
@@ skipping 303 matching lines @@
     template_url = model ? model->GetDefaultSearchProvider() : NULL;
   }
   if (template_url && template_url->id() &&
       template_url->instant_url() &&
       !IsBlacklistedFromInstant(template_url->id()) &&
       template_url->instant_url()->SupportsReplacement()) {
     return template_url;
   }
   return NULL;
 }