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

components/sync_sessions/favicon_cache.cc

 // Copyright 2013 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 "components/sync_sessions/favicon_cache.h"
 
 #include <utility>
 
 #include "base/location.h"
 #include "base/metrics/histogram_macros.h"
@@ skipping 40 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(SyncedFaviconInfo);
 };
 
 // Information for handling local favicon updates. Used in
 // OnFaviconDataAvailable.
 struct LocalFaviconUpdateInfo {
   LocalFaviconUpdateInfo()
       : new_image(false),
         new_tracking(false),
         image_needs_rewrite(false),
-        favicon_info(NULL) {}
+        favicon_info(nullptr) {}
 
   bool new_image;
   bool new_tracking;
   bool image_needs_rewrite;
   SyncedFaviconInfo* favicon_info;
 };
 
 namespace {
 
 // Maximum number of favicons to keep in memory (0 means no limit).
@@ skipping 967 matching lines @@
     favicon_images_sync_processor_->ProcessSyncChanges(FROM_HERE,
                                                        image_deletions);
   }
   if (favicon_tracking_sync_processor_.get()) {
     favicon_tracking_sync_processor_->ProcessSyncChanges(FROM_HERE,
                                                          tracking_deletions);
   }
 }
 
 }  // namespace sync_sessions