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

chrome/browser/sync/test/integration/performance/bookmarks_sync_perf_test.cc

 // Copyright (c) 2011 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 "base/macros.h"
 #include "chrome/browser/sync/test/integration/bookmarks_helper.h"
 #include "chrome/browser/sync/test/integration/performance/sync_timing_helper.h"
 #include "chrome/browser/sync/test/integration/profile_sync_service_harness.h"
 #include "chrome/browser/sync/test/integration/sync_test.h"
 #include "components/bookmarks/browser/bookmark_node.h"
@@ skipping 36 matching lines @@
   // Returns a new unique bookmark title.
   std::string NextIndexedURLTitle();
 
   int url_number_;
   int url_title_number_;
   DISALLOW_COPY_AND_ASSIGN(BookmarksSyncPerfTest);
 };
 
 void BookmarksSyncPerfTest::AddURLs(int profile, int num_urls) {
   for (int i = 0; i < num_urls; ++i) {
-    ASSERT_TRUE(AddURL(
-        profile, 0, NextIndexedURLTitle(), GURL(NextIndexedURL())) != NULL);
+    ASSERT_TRUE(AddURL(profile, 0, NextIndexedURLTitle(),
+                       GURL(NextIndexedURL())) != nullptr);
   }
 }
 
 void BookmarksSyncPerfTest::UpdateURLs(int profile) {
   for (int i = 0;
        i < GetBookmarkBarNode(profile)->child_count();
        ++i) {
     ASSERT_TRUE(SetURL(profile,
                        GetBookmarkBarNode(profile)->GetChild(i),
                        GURL(NextIndexedURL())));
@@ skipping 32 matching lines @@
   dt = TimeMutualSyncCycle(GetClient(0), GetClient(1));
   ASSERT_EQ(kNumBookmarks, GetURLCount(1));
   PrintResult("bookmarks", "update_bookmarks", dt);
 
   // TCM ID - 7566626.
   RemoveURLs(0);
   dt = TimeMutualSyncCycle(GetClient(0), GetClient(1));
   ASSERT_EQ(0, GetURLCount(1));
   PrintResult("bookmarks", "delete_bookmarks", dt);
 }