mojo::Serialize*_() calls now propogate/return validation errors.

mojo/public/cpp/bindings/lib/validation_errors.cc

Index: mojo/public/cpp/bindings/lib/validation_errors.cc
diff --git a/mojo/public/cpp/bindings/lib/validation_errors.cc b/mojo/public/cpp/bindings/lib/validation_errors.cc
index aa5f97a0cefa383d266b850fe610e7518b7843d1..4137ba1065c7c60a2b2c320e3d0a8bb64a1be849 100644
--- a/mojo/public/cpp/bindings/lib/validation_errors.cc
+++ b/mojo/public/cpp/bindings/lib/validation_errors.cc
@@ -11,8 +11,6 @@ namespace internal {
 namespace {
 
 ValidationErrorObserverForTesting* g_validation_error_observer = nullptr;
-SerializationWarningObserverForTesting* g_serialization_warning_observer =
-    nullptr;
 
 }  // namespace
 
@@ -73,26 +71,5 @@ ValidationErrorObserverForTesting::~ValidationErrorObserverForTesting() {
   g_validation_error_observer = nullptr;
 }
 
-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 = nullptr;
-}
-
 }  // namespace internal
 }  // namespace mojo