[Sync] Replacing NULL with nullptr/null throughout sync code.

components/browser_sync/profile_sync_service.cc

Index: components/browser_sync/profile_sync_service.cc
diff --git a/components/browser_sync/profile_sync_service.cc b/components/browser_sync/profile_sync_service.cc
index 86eb0068764fdffdf387853a9811d4bdb6c5ef26..9a488009262479d1bc5a31fba8770e3785fdfc17 100644
--- a/components/browser_sync/profile_sync_service.cc
+++ b/components/browser_sync/profile_sync_service.cc
@@ -364,7 +364,7 @@ void ProfileSyncService::Initialize() {
 #endif
 
 #if !defined(OS_ANDROID)
-  DCHECK(sync_error_controller_ == NULL)
+  DCHECK(sync_error_controller_ == nullptr)
       << "Initialize() called more than once.";
   sync_error_controller_ = base::MakeUnique<syncer::SyncErrorController>(this);
   AddObserver(sync_error_controller_.get());
@@ -430,7 +430,7 @@ bool ProfileSyncService::IsDataTypeControllerRunning(
 
 sync_sessions::OpenTabsUIDelegate* ProfileSyncService::GetOpenTabsUIDelegate() {
   if (!IsDataTypeControllerRunning(syncer::SESSIONS))
-    return NULL;
+    return nullptr;
   return sessions_sync_manager_.get();
 }
 
@@ -1781,7 +1781,7 @@ syncer::UserShare* ProfileSyncService::GetUserShare() const {
     return backend_->GetUserShare();
   }
   NOTREACHED();
-  return NULL;
+  return nullptr;
 }
 
 syncer::SyncCycleSnapshot ProfileSyncService::GetLastCycleSnapshot() const {
@@ -1937,7 +1937,7 @@ void ProfileSyncService::ConsumeCachedPassphraseIfPossible() {
 
 void ProfileSyncService::RequestAccessToken() {
   // Only one active request at a time.
-  if (access_token_request_ != NULL)
+  if (access_token_request_ != nullptr)
     return;
   request_access_token_retry_timer_.Stop();
   OAuth2TokenService::ScopeSet oauth2_scopes;
@@ -2290,7 +2290,7 @@ bool ProfileSyncService::IsSyncRequested() const {
 
 SigninManagerBase* ProfileSyncService::signin() const {
   if (!signin_)
-    return NULL;
+    return nullptr;
   return signin_->GetOriginal();
 }
 
@@ -2393,7 +2393,7 @@ void ProfileSyncService::OverrideNetworkResourcesForTest(
 }
 
 bool ProfileSyncService::HasSyncingBackend() const {
-  return backend_ != NULL;
+  return backend_ != nullptr;
 }
 
 void ProfileSyncService::UpdateFirstSyncTimePref() {
@@ -2406,7 +2406,7 @@ void ProfileSyncService::UpdateFirstSyncTimePref() {
 }
 
 void ProfileSyncService::FlushDirectory() const {
-  // backend_initialized_ implies backend_ isn't NULL and the manager exists.
+  // backend_initialized_ implies backend_ isn't null and the manager exists.
   // If sync is not initialized yet, we fail silently.
   if (backend_initialized_)
     backend_->FlushDirectory();
@@ -2422,7 +2422,7 @@ base::MessageLoop* ProfileSyncService::GetSyncLoopForTest() const {
   } else if (backend_) {
     return backend_->GetSyncLoopForTesting();
   } else {
-    return NULL;
+    return nullptr;
   }
 }