Mojo cpp bindings: remove IsNonNullableValidationEnabled() check

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 0af7790ea192d7a153dede77207a5d4c08803439..e3ce6d6ab785de863bd2229ed770ea45013cde79 100644
--- a/mojo/public/cpp/bindings/lib/validation_errors.cc
+++ b/mojo/public/cpp/bindings/lib/validation_errors.cc
@@ -55,8 +55,6 @@ ValidationErrorObserverForTesting::ValidationErrorObserverForTesting()
     : last_error_(VALIDATION_ERROR_NONE) {
   MOJO_DCHECK(!g_validation_error_observer);
   g_validation_error_observer = this;
-  MOJO_LOG(WARNING) << "Non-nullable validation is turned on for testing but "
-                    << "not for production code yet!";
 }
 
 ValidationErrorObserverForTesting::~ValidationErrorObserverForTesting() {
@@ -85,10 +83,5 @@ SerializationWarningObserverForTesting::
   g_serialization_warning_observer = NULL;
 }
 
-bool IsNonNullableValidationEnabled() {
-  // TODO(yzshen): Remove this function and all call sites.
-  return true;
-}
-
 }  // namespace internal
 }  // namespace mojo