C++ bindings: A struct's Deserialize() now does validation before deserializing.

mojo/public/cpp/bindings/tests/union_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 <utility>
 #include <vector>
 
 #include "mojo/public/cpp/bindings/array.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/public/cpp/bindings/lib/array_internal.h"
@@ skipping 645 matching lines @@
 
 // Serialize a null union and deserialize it back to check that we have a null
 // union.
 TEST(UnionTest, Deserialize_NullableUnion) {
   char buf[1024];
   SmallStructPtr small_struct = SmallStruct::New();
   small_struct->Serialize(buf, sizeof(buf));
   EXPECT_TRUE(small_struct->pod_union.is_null());
 
   SmallStructPtr deserialized_struct = SmallStruct::New();
-  deserialized_struct->Deserialize(buf);
-
+  EXPECT_TRUE(deserialized_struct->Deserialize(buf, sizeof(buf)));
   EXPECT_TRUE(deserialized_struct->pod_union.is_null());
 }
 
 // Validation passes with nullable null union containing non-nullable objects.
 TEST(UnionTest, Validation_NullableObjectUnion) {
   Environment environment;
   StructNullObjectUnionPtr small_struct(StructNullObjectUnion::New());
 
   size_t size = GetSerializedSize_(*small_struct);
 
@@ skipping 609 matching lines @@
   PodUnionPtr pod(PodUnion::New());
   pod->set_f_int16(16);
 
   ptr->Echo(pod.Pass(),
             [](PodUnionPtr out) { EXPECT_EQ(16, out->get_f_int16()); });
   run_loop.RunUntilIdle();
 }
 
 }  // namespace test
 }  // namespace mojo