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

chrome/browser/sync/glue/synced_window_delegate_android.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/sync/glue/synced_window_delegate_android.h"
 
 #include "chrome/browser/android/tab_android.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/sync/glue/synced_tab_delegate_android.h"
 #include "chrome/browser/ui/android/tab_model/tab_model.h"
@@ skipping 41 matching lines @@
 }
 
 bool SyncedWindowDelegateAndroid::IsTabPinned(
     const SyncedTabDelegate* tab) const {
   return false;
 }
 
 SyncedTabDelegate* SyncedWindowDelegateAndroid::GetTabAt(int index) const {
   // After a restart, it is possible for the Tab to be null during startup.
   TabAndroid* tab = tab_model_->GetTabAt(index);
-  return tab ? tab->GetSyncedTabDelegate() : NULL;
+  return tab ? tab->GetSyncedTabDelegate() : nullptr;
 }
 
 SessionID::id_type SyncedWindowDelegateAndroid::GetTabIdAt(int index) const {
   SyncedTabDelegate* tab = GetTabAt(index);
   return tab ? tab->GetSessionId() : -1;
 }
 
 bool SyncedWindowDelegateAndroid::IsSessionRestoreInProgress() const {
   return tab_model_->IsSessionRestoreInProgress();
 }
 
 bool SyncedWindowDelegateAndroid::ShouldSync() const {
   return true;
 }
 
 }  // namespace browser_sync