[Sync] Replacing NULL with nullptr in code and null in comments for components/sync/

components/sync/syncable/syncable_unittest.cc

 // Copyright 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 <stdint.h>
 
 #include <memory>
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 97 matching lines @@
     const base::FilePath& backing_filepath) {
   TestBackingStore* backing_store =
       new TestBackingStore(dir_name, backing_filepath);
   return new TestDirectory(encryptor, handler, backing_store);
 }
 
 TestDirectory::TestDirectory(
     Encryptor* encryptor,
     const WeakHandle<UnrecoverableErrorHandler>& handler,
     TestBackingStore* backing_store)
-    : Directory(backing_store, handler, base::Closure(), NULL, NULL),
+    : Directory(backing_store, handler, base::Closure(), nullptr, nullptr),
       backing_store_(backing_store) {}
 
 TestDirectory::~TestDirectory() {}
 
 // crbug.com/144422
 #if defined(OS_ANDROID)
 #define MAYBE_FailInitialWrite DISABLED_FailInitialWrite
 #else
 #define MAYBE_FailInitialWrite FailInitialWrite
 #endif
@@ skipping 420 matching lines @@
   TestUnrecoverableErrorHandler handler_;
   NullDirectoryChangeDelegate delegate_;
 };
 
 TEST_F(SyncableDirectoryManagement, TestFileRelease) {
   base::FilePath path =
       temp_dir_.GetPath().Append(Directory::kSyncDatabaseFilename);
 
   {
     Directory dir(new OnDiskDirectoryBackingStore("ScopeTest", path),
-                  MakeWeakHandle(handler_.GetWeakPtr()), base::Closure(), NULL,
-                  NULL);
+                  MakeWeakHandle(handler_.GetWeakPtr()), base::Closure(),
+                  nullptr, nullptr);
     DirOpenResult result =
         dir.Open("ScopeTest", &delegate_, NullTransactionObserver());
     ASSERT_EQ(result, OPENED);
   }
 
   // Destroying the directory should have released the backing database file.
   ASSERT_TRUE(base::DeleteFile(path, true));
 }
 
 class SyncableClientTagTest : public SyncableDirectoryTest {
@@ skipping 85 matching lines @@
 TEST_F(SyncableClientTagTest, TestClientTagIndexDuplicateServer) {
   EXPECT_TRUE(CreateWithDefaultTag(factory_.NewServerId(), true));
   EXPECT_FALSE(CreateWithDefaultTag(factory_.NewServerId(), true));
   EXPECT_FALSE(CreateWithDefaultTag(factory_.NewServerId(), false));
   EXPECT_FALSE(CreateWithDefaultTag(factory_.NewLocalId(), false));
   EXPECT_FALSE(CreateWithDefaultTag(factory_.NewLocalId(), true));
 }
 
 }  // namespace syncable
 }  // namespace syncer