[SyncFS] Use nullptr instead of NULL

chrome/browser/sync_file_system/local/canned_syncable_file_system.cc

Index: chrome/browser/sync_file_system/local/canned_syncable_file_system.cc
diff --git a/chrome/browser/sync_file_system/local/canned_syncable_file_system.cc b/chrome/browser/sync_file_system/local/canned_syncable_file_system.cc
index d6bdb8b83b42f74e57943d378489b44df49eddf8..c636e35ed25b8f472e0d61777ddcfc5bb7830bcf 100644
--- a/chrome/browser/sync_file_system/local/canned_syncable_file_system.cc
+++ b/chrome/browser/sync_file_system/local/canned_syncable_file_system.cc
@@ -92,8 +92,8 @@ void EnsureRunningOn(base::SingleThreadTaskRunner* runner) {
 void VerifySameTaskRunner(
     base::SingleThreadTaskRunner* runner1,
     base::SingleThreadTaskRunner* runner2) {
-  ASSERT_TRUE(runner1 != NULL);
-  ASSERT_TRUE(runner2 != NULL);
+  ASSERT_TRUE(runner1 != nullptr);
+  ASSERT_TRUE(runner2 != nullptr);
   runner1->PostTask(FROM_HERE,
                     base::Bind(&EnsureRunningOn, make_scoped_refptr(runner2)));
 }
@@ -255,7 +255,7 @@ void CannedSyncableFileSystem::SetUp(QuotaMode quota_mode) {
       file_task_runner_.get(),
       storage::ExternalMountPoints::CreateRefCounted().get(),
       storage_policy.get(),
-      quota_manager_.get() ? quota_manager_->proxy() : NULL,
+      quota_manager_.get() ? quota_manager_->proxy() : nullptr,
       additional_backends.Pass(),
       std::vector<storage::URLRequestAutoMountHandler>(),
       data_dir_.path(),
@@ -265,8 +265,8 @@ void CannedSyncableFileSystem::SetUp(QuotaMode quota_mode) {
 }
 
 void CannedSyncableFileSystem::TearDown() {
-  quota_manager_ = NULL;
-  file_system_context_ = NULL;
+  quota_manager_ = nullptr;
+  file_system_context_ = nullptr;
 
   // Make sure we give some more time to finish tasks on other threads.
   EnsureLastTaskRuns(io_task_runner_.get());