Add PrerenderLocalPredictor, which will eventually perform

chrome/browser/history/history.cc

Index: chrome/browser/history/history.cc
===================================================================
--- chrome/browser/history/history.cc	(revision 133528)
+++ chrome/browser/history/history.cc	(working copy)
@@ -40,6 +40,7 @@
 #include "chrome/browser/history/in_memory_history_backend.h"
 #include "chrome/browser/history/in_memory_url_index.h"
 #include "chrome/browser/history/top_sites.h"
+#include "chrome/browser/history/visit_database.h"
 #include "chrome/browser/history/visit_filter.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
@@ -127,6 +128,13 @@
                    history_service_.get(), backend_id));
   }
 
+  virtual void NotifyVisitDBObserversOnAddVisit(
+      const history::BriefVisitInfo& info) OVERRIDE {
+    // Since the notification method can be run on any thread, we can
+    // call it right away.
+    history_service_->NotifyVisitDBObserversOnAddVisit(info);
+  }
+
  private:
   scoped_refptr<HistoryService> history_service_;
   MessageLoop* message_loop_;
@@ -143,7 +151,9 @@
       current_backend_id_(-1),
       bookmark_service_(NULL),
       no_db_(false),
-      needs_top_sites_migration_(false) {
+      needs_top_sites_migration_(false),
+      visit_database_observers_(
+          new ObserverListThreadSafe<history::VisitDatabaseObserver>()) {
 }
 
 HistoryService::HistoryService(Profile* profile)
@@ -153,7 +163,9 @@
       current_backend_id_(-1),
       bookmark_service_(NULL),
       no_db_(false),
-      needs_top_sites_migration_(false) {
+      needs_top_sites_migration_(false),
+      visit_database_observers_(
+          new ObserverListThreadSafe<history::VisitDatabaseObserver>()) {
   DCHECK(profile_);
   registrar_.Add(this, chrome::NOTIFICATION_HISTORY_URLS_DELETED,
                  content::Source<Profile>(profile_));
@@ -892,3 +904,19 @@
   ScheduleAndForget(PRIORITY_NORMAL,
                     &HistoryBackend::MigrateThumbnailsDatabase);
 }
+
+void HistoryService::AddVisitDatabaseObserver(
+    history::VisitDatabaseObserver* observer) {
+  visit_database_observers_->AddObserver(observer);
+}
+
+void HistoryService::RemoveVisitDatabaseObserver(
+    history::VisitDatabaseObserver* observer) {
+  visit_database_observers_->RemoveObserver(observer);
+}
+
+void HistoryService::NotifyVisitDBObserversOnAddVisit(
+    const history::BriefVisitInfo& info) {
+  visit_database_observers_->Notify(
+      &history::VisitDatabaseObserver::OnAddVisit, info);
+}