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

components/sync/test/fake_server/fake_server_verifier.cc

Index: components/sync/test/fake_server/fake_server_verifier.cc
diff --git a/components/sync/test/fake_server/fake_server_verifier.cc b/components/sync/test/fake_server/fake_server_verifier.cc
index 113656979f6b3111c0e251cc4197a8b922fac24c..b2497ea8d433e479e2db4fcda33374276d93b9ca 100644
--- a/components/sync/test/fake_server/fake_server_verifier.cc
+++ b/components/sync/test/fake_server/fake_server_verifier.cc
@@ -77,7 +77,7 @@ AssertionResult FakeServerVerifier::VerifyEntityCountByType(
   }
 
   string model_type_string = ModelTypeToString(model_type);
-  base::ListValue* entity_list = NULL;
+  base::ListValue* entity_list = nullptr;
   if (!entities->GetList(model_type_string, &entity_list)) {
     return UnknownTypeAssertionFailure(model_type_string);
   } else if (expected_count != entity_list->GetSize()) {
@@ -101,7 +101,7 @@ AssertionResult FakeServerVerifier::VerifyEntityCountByTypeAndName(
   }
 
   string model_type_string = ModelTypeToString(model_type);
-  base::ListValue* entity_list = NULL;
+  base::ListValue* entity_list = nullptr;
   size_t actual_count = 0;
   if (entities->GetList(model_type_string, &entity_list)) {
     base::StringValue name_value(name);