[Instant] Default Search Provider change redirects to local NTP in some cases

chrome/browser/search/instant_service.cc

 // Copyright 2013 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/search/instant_service.h"
 
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/history/top_sites_factory.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/search/instant_io_context.h"
@@ skipping 389 matching lines @@
       UIThreadSearchTermsData(profile_));
   if (default_search_provider_changed) {
     previous_default_search_provider_.reset(
         template_url ? new TemplateURLData(template_url->data()) : NULL);
   }
 
   // Note that, even if the TemplateURL for the Default Search Provider has not
   // changed, the effective URLs might change if they reference the Google base
   // URL. The TemplateURLService will notify us when the effective URL changes
   // in this way but it's up to us to do the work to check both.
+  bool google_base_url_domain_changed = false;
   GURL google_base_url(UIThreadSearchTermsData(profile_).GoogleBaseURLValue());
   if (google_base_url != previous_google_base_url_) {
     previous_google_base_url_ = google_base_url;
     if (template_url && template_url->HasGoogleBaseURLs(
             UIThreadSearchTermsData(profile_)))
-      default_search_provider_changed = true;
+      google_base_url_domain_changed = true;
   }
 
-  if (default_search_provider_changed) {
+  if (default_search_provider_changed || google_base_url_domain_changed) {
     ResetInstantSearchPrerenderer();
-    FOR_EACH_OBSERVER(InstantServiceObserver, observers_,
-                      DefaultSearchProviderChanged());
+    FOR_EACH_OBSERVER(
+        InstantServiceObserver, observers_,
+        DefaultSearchProviderChanged(google_base_url_domain_changed));
   }
 }
 
 void InstantService::TopSitesLoaded(history::TopSites* top_sites) {
 }
 
 void InstantService::TopSitesChanged(history::TopSites* top_sites) {
   top_sites->GetMostVisitedURLs(
       base::Bind(&InstantService::OnMostVisitedItemsReceived,
                  weak_ptr_factory_.GetWeakPtr()),
       false);
 }
 
 void InstantService::ResetInstantSearchPrerenderer() {
   if (!chrome::ShouldPrefetchSearchResults())
     return;
 
   GURL url(chrome::GetSearchResultPrefetchBaseURL(profile_));
   instant_prerenderer_.reset(
       url.is_valid() ? new InstantSearchPrerenderer(profile_, url) : NULL);
 }