Introduce ability to register callback with GoogleURLTracker

chrome/browser/google/google_url_tracker.h

Index: chrome/browser/google/google_url_tracker.h
diff --git a/chrome/browser/google/google_url_tracker.h b/chrome/browser/google/google_url_tracker.h
index ab930003369eb8a6b51b4177d195f2914145e5b8..06b3cb8c534949f5e5f3e5aed34b659219c11949 100644
--- a/chrome/browser/google/google_url_tracker.h
+++ b/chrome/browser/google/google_url_tracker.h
@@ -10,6 +10,7 @@
 #include <utility>
 
 #include "base/callback_forward.h"
+#include "base/callback_list.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
@@ -49,6 +50,10 @@ class GoogleURLTracker : public net::URLFetcherDelegate,
                          public net::NetworkChangeNotifier::IPAddressObserver,
                          public KeyedService {
  public:
+  // Callback that is called when the Google URL is updated. The arguments are
+  // the old and new URLs.
+  typedef base::Callback<void(GURL, GURL)> OnGoogleURLUpdatedCallback;
+
   // The contents of the Details for a NOTIFICATION_GOOGLE_URL_UPDATED.
   typedef std::pair<GURL, GURL> UpdatedDetails;
 
@@ -125,6 +130,11 @@ class GoogleURLTracker : public net::URLFetcherDelegate,
   virtual void OnTabClosed(
       content::NavigationController* navigation_controller);
 
+  scoped_ptr<base::CallbackList<void(GURL, GURL)>::Subscription>
+  RegisterCallback(const OnGoogleURLUpdatedCallback& cb) {
+    return callback_list_.Add(cb);

[Peter Kasting, 2014/05/15 21:12:52]

Add() is not a cheap accessor (based on its name), so please define this
out-of-line.

[blundell, 2014/05/16 09:09:55]

Done.

+  }
+
   static const char kDefaultGoogleHomepage[];
   static const char kSearchDomainCheckURL[];
 
@@ -175,6 +185,12 @@ class GoogleURLTracker : public net::URLFetcherDelegate,
       const GoogleURLTrackerMapEntry& map_entry,
       bool must_be_listening_for_commit);
 
+  void NotifyGoogleURLUpdated(GURL old_url, GURL new_url) {
+    callback_list_.Notify(old_url, new_url);

[Peter Kasting, 2014/05/15 21:12:52]

Again, define this out-of-line.

[blundell, 2014/05/16 09:09:55]

Done.

+  }
+
+  base::CallbackList<void(GURL, GURL)> callback_list_;

[Peter Kasting, 2014/05/15 21:12:52]

Nit: Consider a typedef for this type and/or base::CallbackList<void(GURL,
GURL)>::Subscription.

[blundell, 2014/05/16 09:09:55]

Done.

+
   Profile* profile_;
 
   scoped_ptr<GoogleURLTrackerNavigationHelper> nav_helper_;