Use the DefaultSearchManager as the exclusive authority on DSE, ignoring Web Data.

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 <vector>
 
 #include "base/logging.h"
 #include "base/prefs/pref_service.h"
@@ skipping 52 matching lines @@
   color.b = SkColorGetB(sKColor);
   color.a = SkColorGetA(sKColor);
   return color;
 }
 
 }  // namespace
 
 InstantService::InstantService(Profile* profile)
     : profile_(profile),
       omnibox_start_margin_(chrome::kDisableStartMargin),
-      weak_ptr_factory_(this) {
+      weak_ptr_factory_(this),
+      current_search_result_prefetch_base_url_(
+          chrome::GetSearchResultPrefetchBaseURL(profile_)),
+      default_search_engine_watcher_(this) {
   // Stub for unit tests.
   if (!BrowserThread::CurrentlyOn(BrowserThread::UI))
     return;
 
+  TemplateURLService* template_url_service =
+      TemplateURLServiceFactory::GetForProfile(profile_);
+  if (template_url_service)
+    template_url_service->AddObserver(&default_search_engine_watcher_);
+
   ResetInstantSearchPrerenderer();
 
   registrar_.Add(this,
                  content::NOTIFICATION_RENDERER_PROCESS_CREATED,
                  content::NotificationService::AllSources());
   registrar_.Add(this,
                  content::NOTIFICATION_RENDERER_PROCESS_TERMINATED,
                  content::NotificationService::AllSources());
 
   history::TopSites* top_sites = profile_->GetTopSites();
@@ skipping 31 matching lines @@
 
   content::URLDataSource::Add(
       profile_, new FaviconSource(profile_, FaviconSource::FAVICON));
   content::URLDataSource::Add(profile_, new LocalNtpSource(profile_));
   content::URLDataSource::Add(profile_, new MostVisitedIframeSource());
   if (suggestions::SuggestionsService::IsEnabled()) {
     content::URLDataSource::Add(
         profile_, new suggestions::SuggestionsSource(profile_));
   }
 
-  profile_pref_registrar_.Init(profile_->GetPrefs());
-  profile_pref_registrar_.Add(
-      prefs::kDefaultSearchProviderID,
-      base::Bind(&InstantService::OnDefaultSearchProviderChanged,
-                 base::Unretained(this)));
-
   registrar_.Add(this, chrome::NOTIFICATION_GOOGLE_URL_UPDATED,
                  content::Source<Profile>(profile_->GetOriginalProfile()));
 }
 
 InstantService::~InstantService() {
 }
 
 void InstantService::AddInstantProcess(int process_id) {
   process_ids_.insert(process_id);
 
@@ skipping 48 matching lines @@
   if (!theme_info_)
     OnThemeChanged(ThemeServiceFactory::GetForProfile(profile_));
   else
     OnThemeChanged(NULL);
 }
 
 void InstantService::UpdateMostVisitedItemsInfo() {
   NotifyAboutMostVisitedItems();
 }
 
+InstantService::DefaultSearchEngineWatcher::DefaultSearchEngineWatcher(
+    InstantService* outer)
+    : outer_(outer) {
+}
+
+void InstantService::DefaultSearchEngineWatcher::OnTemplateURLServiceChanged() {
+  outer_->OnTemplateURLServiceChanged();
+}
+
 void InstantService::Shutdown() {
   process_ids_.clear();
 
   if (instant_io_context_.get()) {
     BrowserThread::PostTask(
         BrowserThread::IO,
         FROM_HERE,
         base::Bind(&InstantIOContext::ClearInstantProcessesOnIO,
                    instant_io_context_));
   }
@@ skipping 209 matching lines @@
 
   // Only the scheme changed. Ignore it since we do not prompt the user in this
   // case.
   if (net::StripWWWFromHost(details->first) ==
       net::StripWWWFromHost(details->second))
     return;
 
   FOR_EACH_OBSERVER(InstantServiceObserver, observers_, GoogleURLUpdated());
 }
 
-void InstantService::OnDefaultSearchProviderChanged(
-    const std::string& pref_name) {
-  DCHECK_EQ(pref_name, std::string(prefs::kDefaultSearchProviderID));
+void InstantService::OnTemplateURLServiceChanged() {
   const TemplateURL* template_url = TemplateURLServiceFactory::GetForProfile(
       profile_)->GetDefaultSearchProvider();
   if (!template_url) {
     // A NULL |template_url| could mean either this notification is sent during
     // the browser start up operation or the user now has no default search
     // provider. There is no way for the user to reach this state using the
     // Chrome settings. Only explicitly poking at the DB or bugs in the Sync
     // could cause that, neither of which we support.
     return;
   }
+  GURL new_search_result_prefetch_base_url(
+      chrome::GetSearchResultPrefetchBaseURL(profile_));
+  if (new_search_result_prefetch_base_url ==
+      current_search_result_prefetch_base_url_)
+    return;
+  current_search_result_prefetch_base_url_ =
+      new_search_result_prefetch_base_url;
 
   ResetInstantSearchPrerenderer();
 
   FOR_EACH_OBSERVER(
       InstantServiceObserver, observers_, DefaultSearchProviderChanged());
 }
 
 void InstantService::ResetInstantSearchPrerenderer() {
   if (!chrome::ShouldPrefetchSearchResults())
     return;
 
-  GURL url(chrome::GetSearchResultPrefetchBaseURL(profile_));
-  if (url.is_valid())
-    instant_prerenderer_.reset(new InstantSearchPrerenderer(profile_, url));
-  else
+  if (current_search_result_prefetch_base_url_.is_valid()) {
+    instant_prerenderer_.reset(new InstantSearchPrerenderer(
+        profile_, current_search_result_prefetch_base_url_));
+  } else {
     instant_prerenderer_.reset();
+  }
 }