[SyncFS] Use nullptr instead of NULL

chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc

Index: chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc
diff --git a/chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc b/chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc
index e4316ca2b09d5314178cd448008f1b4076803679..730d719d304cfd65455294566d65e85714e29795 100644
--- a/chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc
+++ b/chrome/browser/sync_file_system/drive_backend/metadata_database_unittest.cc
@@ -232,7 +232,7 @@ class MetadataDatabaseTest : public testing::TestWithParam<bool> {
     if (!file.should_be_absent) {
       if (file.tracker_only) {
         EXPECT_FALSE(metadata_database()->FindFileByFileID(
-            file.metadata.file_id(), NULL));
+            file.metadata.file_id(), nullptr));
       } else {
         VerifyFile(file.metadata);
       }
@@ -241,9 +241,9 @@ class MetadataDatabaseTest : public testing::TestWithParam<bool> {
     }
 
     EXPECT_FALSE(metadata_database()->FindFileByFileID(
-        file.metadata.file_id(), NULL));
+        file.metadata.file_id(), nullptr));
     EXPECT_FALSE(metadata_database()->FindTrackerByTrackerID(
-        file.tracker.tracker_id(), NULL));
+        file.tracker.tracker_id(), nullptr));
   }
 
   void VerifyTrackedFiles(const TrackedFile** tracked_files, int size) {
@@ -254,7 +254,7 @@ class MetadataDatabaseTest : public testing::TestWithParam<bool> {
   MetadataDatabase* metadata_database() { return metadata_database_.get(); }
 
   scoped_ptr<LevelDBWrapper> InitializeLevelDB() {
-    leveldb::DB* db = NULL;
+    leveldb::DB* db = nullptr;
     leveldb::Options options;
     options.create_if_missing = true;
     options.max_open_files = 0;  // Use minimum.
@@ -1141,7 +1141,7 @@ TEST_P(MetadataDatabaseTest, DumpFiles) {
       metadata_database()->DumpFiles(app_root.tracker.app_id());
   ASSERT_EQ(2u, files->GetSize());
 
-  base::DictionaryValue* file = NULL;
+  base::DictionaryValue* file = nullptr;
   std::string str;
 
   ASSERT_TRUE(files->GetDictionary(0, &file));