IDL: Support union type arrays and sequences for method arguments

Source/bindings/templates/union.cpp

 // 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.
 
 // This file has been auto-generated by {{code_generator}}. DO NOT MODIFY!
 
 #include "config.h"
 #include "{{header_filename}}"
 
 {% macro assign_and_return_if_hasinstance(member) %}
@@ skipping 133 matching lines @@
     {% for member in container.members %}
     case {{container.cpp_class}}::{{member.specific_type_enum}}:
         return {{member.cpp_value_to_v8_value}};
     {% endfor %}
     default:
         ASSERT_NOT_REACHED();
     }
     return v8::Handle<v8::Value>();
 }
 
+{{container.cpp_class}} NativeValueTraits<{{container.cpp_class}}>::nativeValue(const v8::Handle<v8::Value>& value, v8::Isolate* isolate, ExceptionState& exceptionState)
+{
+    {{container.cpp_class}} impl;
+    V8{{container.cpp_class}}::toImpl(isolate, value, impl, exceptionState);
+    return impl;
+}
+
 {% endfor %}
 } // namespace blink