mojo: Allow circular dependencies between structs

mojo/public/cpp/bindings/tests/serialization_warning_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.
 
 // Serialization warnings are only recorded in debug build.
 #ifndef NDEBUG
 
 #include "mojo/public/cpp/bindings/array.h"
 #include "mojo/public/cpp/bindings/lib/array_internal.h"
 #include "mojo/public/cpp/bindings/lib/array_serialization.h"
@@ skipping 26 matching lines @@
 
   return array.Pass();
 }
 
 class SerializationWarningTest : public testing::Test {
  public:
   virtual ~SerializationWarningTest() {}
 
  protected:
   template <typename T>
-  void TestWarning(T obj, mojo::internal::ValidationError expected_warning) {
+  void TestWarning(StructPtr<T> obj,
+                   mojo::internal::ValidationError expected_warning) {
     warning_observer_.set_last_warning(mojo::internal::VALIDATION_ERROR_NONE);
 
     mojo::internal::FixedBuffer buf(GetSerializedSize_(obj));
     typename T::Data_* data;
     Serialize_(obj.Pass(), &buf, &data);
 
     EXPECT_EQ(expected_warning, warning_observer_.last_warning());
   }
 
   template <typename ValidateParams, typename T>
@@ skipping 143 matching lines @@
                    ArrayValidateParams<0, false, NoValidateParams> > >(
       test_array.Pass(),
       mojo::internal::VALIDATION_ERROR_UNEXPECTED_ARRAY_HEADER);
 }
 
 }  // namespace
 }  // namespace test
 }  // namespace mojo
 
 #endif