Switch to standard integer types in components/, part 2 of 4.

components/invalidation/impl/unacked_invalidation_set_unittest.cc

 // Copyright 2014 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/invalidation/impl/unacked_invalidation_set.h"
 
+#include <stddef.h>
+
 #include "base/json/json_string_value_serializer.h"
 #include "components/invalidation/impl/unacked_invalidation_set_test_util.h"
 #include "components/invalidation/public/object_id_invalidation_map.h"
 #include "components/invalidation/public/single_object_invalidation_set.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace syncer {
 
 class UnackedInvalidationSetTest : public testing::Test {
  public:
@@ skipping 196 matching lines @@
   unacked_invalidations_.Add(inv2);
   unacked_invalidations_.Add(inv3);
 
   UnackedInvalidationSet deserialized = SerializeDeserialize();
   EXPECT_THAT(unacked_invalidations_, test_util::Eq(deserialized));
 }
 
 }  // namespace
 
 }  // namespace syncer