sync: don't allow NULL profile in ProfileSyncService and friends

chrome/browser/invalidation/invalidator_storage.h

Index: chrome/browser/invalidation/invalidator_storage.h
diff --git a/chrome/browser/invalidation/invalidator_storage.h b/chrome/browser/invalidation/invalidator_storage.h
index d0b48a2e853d9f2d9cda1a2efc7dffa39bca8f54..4a2fdd5b8513cb0fc3c18cf362467b294a894a94 100644
--- a/chrome/browser/invalidation/invalidator_storage.h
+++ b/chrome/browser/invalidation/invalidator_storage.h
@@ -33,8 +33,7 @@ class InvalidatorStorage : public base::SupportsWeakPtr<InvalidatorStorage>,
  public:
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
-  // |pref_service| may be NULL (for unit tests), but in that case no setter
-  // methods should be called. Does not own |pref_service|.
+  // |pref_service| may not be NULL. Does not own |pref_service|.
   explicit InvalidatorStorage(PrefService* pref_service);
   virtual ~InvalidatorStorage();
 
@@ -93,7 +92,6 @@ class InvalidatorStorage : public base::SupportsWeakPtr<InvalidatorStorage>,
   static void DeserializeMap(const base::DictionaryValue* max_versions_dict,
                              syncer::InvalidationStateMap* map);
 
-  // May be NULL.
   PrefService* const pref_service_;
 
   DISALLOW_COPY_AND_ASSIGN(InvalidatorStorage);