[Sync] Replacing NULL with nullptr in code and null in comments for components/sync/

components/sync/engine_impl/apply_control_data_updates_unittest.cc

Index: components/sync/engine_impl/apply_control_data_updates_unittest.cc
diff --git a/components/sync/engine_impl/apply_control_data_updates_unittest.cc b/components/sync/engine_impl/apply_control_data_updates_unittest.cc
index b5c92bc413961a524565c7a7a52bfd0e2f99ab29..b72507ff6ae936cbae94d4d203e2694fea47592f 100644
--- a/components/sync/engine_impl/apply_control_data_updates_unittest.cc
+++ b/components/sync/engine_impl/apply_control_data_updates_unittest.cc
@@ -133,20 +133,20 @@ TEST_F(ApplyControlDataUpdatesTest, EncryptUnsyncedChanges) {
   // First item is a folder
   Id folder_id = id_factory_.NewLocalId();
   entry_factory_->CreateUnsyncedItem(folder_id, id_factory_.root(), "folder",
-                                     true, BOOKMARKS, NULL);
+                                     true, BOOKMARKS, nullptr);
   // Next five items are children of the folder
   size_t i;
   size_t batch_s = 5;
   for (i = 0; i < batch_s; ++i) {
     entry_factory_->CreateUnsyncedItem(id_factory_.NewLocalId(), folder_id,
                                        base::StringPrintf("Item %" PRIuS "", i),
-                                       false, BOOKMARKS, NULL);
+                                       false, BOOKMARKS, nullptr);
   }
   // Next five items are children of the root.
   for (; i < 2 * batch_s; ++i) {
     entry_factory_->CreateUnsyncedItem(
         id_factory_.NewLocalId(), id_factory_.root(),
-        base::StringPrintf("Item %" PRIuS "", i), false, BOOKMARKS, NULL);
+        base::StringPrintf("Item %" PRIuS "", i), false, BOOKMARKS, nullptr);
   }
 
   KeyParams params = {"localhost", "dummy", "foobar"};
@@ -244,20 +244,20 @@ TEST_F(ApplyControlDataUpdatesTest, CannotEncryptUnsyncedChanges) {
   // First item is a folder
   Id folder_id = id_factory_.NewLocalId();
   entry_factory_->CreateUnsyncedItem(folder_id, id_factory_.root(), "folder",
-                                     true, BOOKMARKS, NULL);
+                                     true, BOOKMARKS, nullptr);
   // Next five items are children of the folder
   size_t i;
   size_t batch_s = 5;
   for (i = 0; i < batch_s; ++i) {
     entry_factory_->CreateUnsyncedItem(id_factory_.NewLocalId(), folder_id,
                                        base::StringPrintf("Item %" PRIuS "", i),
-                                       false, BOOKMARKS, NULL);
+                                       false, BOOKMARKS, nullptr);
   }
   // Next five items are children of the root.
   for (; i < 2 * batch_s; ++i) {
     entry_factory_->CreateUnsyncedItem(
         id_factory_.NewLocalId(), id_factory_.root(),
-        base::StringPrintf("Item %" PRIuS "", i), false, BOOKMARKS, NULL);
+        base::StringPrintf("Item %" PRIuS "", i), false, BOOKMARKS, nullptr);
   }
 
   // We encrypt with new keys, triggering the local cryptographer to be unready