Mojo: Add warning of invalid serialization results (in debug build).

mojo/public/cpp/bindings/lib/validation_errors.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 "mojo/public/cpp/bindings/lib/validation_errors.h"
 
 #include "mojo/public/cpp/environment/logging.h"
 
 namespace mojo {
 namespace internal {
 namespace {
 
 ValidationErrorObserverForTesting* g_validation_error_observer = NULL;
+SerializationWarningObserverForTesting* g_serialization_warning_observer = NULL;
 
 }  // namespace
 
 const char* ValidationErrorToString(ValidationError error) {
   switch (error) {
     case VALIDATION_ERROR_NONE:
       return "VALIDATION_ERROR_NONE";
     case VALIDATION_ERROR_MISALIGNED_OBJECT:
       return "VALIDATION_ERROR_MISALIGNED_OBJECT";
     case VALIDATION_ERROR_ILLEGAL_MEMORY_RANGE:
@@ skipping 32 matching lines @@
   g_validation_error_observer = this;
   MOJO_LOG(WARNING) << "Non-nullable validation is turned on for testing but "
                     << "not for production code yet!";
 }
 
 ValidationErrorObserverForTesting::~ValidationErrorObserverForTesting() {
   MOJO_DCHECK(g_validation_error_observer == this);
   g_validation_error_observer = NULL;
 }
 
+bool ReportSerializationWarning(ValidationError error) {
+  if (g_serialization_warning_observer) {
+    g_serialization_warning_observer->set_last_warning(error);
+    return true;
+  }
+
+  return false;
+}
+
+SerializationWarningObserverForTesting::SerializationWarningObserverForTesting()
+    : last_warning_(VALIDATION_ERROR_NONE) {
+  MOJO_DCHECK(!g_serialization_warning_observer);
+  g_serialization_warning_observer = this;
+}
+
+SerializationWarningObserverForTesting::
+~SerializationWarningObserverForTesting() {
+  MOJO_DCHECK(g_serialization_warning_observer == this);
+  g_serialization_warning_observer = NULL;
+}
+
 bool IsNonNullableValidationEnabled() {
-  return !!g_validation_error_observer;
+  return g_validation_error_observer || g_serialization_warning_observer;
 }
 
 }  // namespace internal
 }  // namespace mojo