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

chrome/browser/search/instant_service.h

Index: chrome/browser/search/instant_service.h
diff --git a/chrome/browser/search/instant_service.h b/chrome/browser/search/instant_service.h
index 393d0721fa06c06b3657c61f5e59482b230145f6..4cb97ed2c55f17cd733bf9053ca024c6d36da814 100644
--- a/chrome/browser/search/instant_service.h
+++ b/chrome/browser/search/instant_service.h
@@ -15,16 +15,16 @@
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
-#include "base/prefs/pref_change_registrar.h"
 #include "chrome/browser/google/google_url_tracker.h"
 #include "chrome/browser/history/history_types.h"
+#include "chrome/browser/search_engines/template_url_service_observer.h"
 #include "chrome/browser/ui/search/instant_search_prerenderer.h"
 #include "chrome/common/instant_types.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
+#include "url/gurl.h"
 
-class GURL;
 class InstantIOContext;
 class InstantServiceObserver;
 class InstantTestBase;
@@ -42,7 +42,8 @@ class URLRequest;
 
 // Tracks render process host IDs that are associated with Instant.
 class InstantService : public KeyedService,
-                       public content::NotificationObserver {
+                       public content::NotificationObserver,
+                       public TemplateURLServiceObserver {
  public:
   explicit InstantService(Profile* profile);
   virtual ~InstantService();
@@ -118,6 +119,10 @@ class InstantService : public KeyedService,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
+  // Overridden from TemplateURLServiceObserver:
+  virtual void OnTemplateURLServiceChanged() OVERRIDE;
+
+
   // Called when a renderer process is terminated.
   void OnRendererProcessTerminated(int process_id);
 
@@ -135,8 +140,6 @@ class InstantService : public KeyedService,
   void OnGoogleURLUpdated(Profile* profile,
                           GoogleURLTracker::UpdatedDetails* details);
 
-  void OnDefaultSearchProviderChanged(const std::string& pref_name);
-
   void ResetInstantSearchPrerenderer();
 
   Profile* const profile_;
@@ -158,8 +161,6 @@ class InstantService : public KeyedService,
 
   content::NotificationRegistrar registrar_;
 
-  PrefChangeRegistrar profile_pref_registrar_;
-
   scoped_refptr<InstantIOContext> instant_io_context_;
 
   // Set to NULL if the default search provider does not support Instant.
@@ -168,6 +169,10 @@ class InstantService : public KeyedService,
   // Used for Top Sites async retrieval.
   base::WeakPtrFactory<InstantService> weak_ptr_factory_;
 
+  // Used to avoid resetting the instant_prerenderer_ if an unrelated change to
+  // the TemplateURLService occurs.
+  GURL current_search_result_prefetch_base_url_;
+
   DISALLOW_COPY_AND_ASSIGN(InstantService);
 };