IDL: Values for dictionaries should be a object, null or undefined

Source/bindings/templates/dictionary_v8.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 "{{v8_class}}.h"
 
 {% for filename in cpp_includes if filename != '%s.h' % v8_class %}
 #include "{{filename}}"
 {% endfor %}
 
 namespace blink {
 
 {{cpp_class}}* {{v8_class}}::toImpl(v8::Isolate* isolate, v8::Handle<v8::Value> v8Value, ExceptionState& exceptionState)
 {
+    ASSERT(isUndefinedOrNull(v8Value) || v8Value->IsObject());
+
     {{cpp_class}}* impl = {{cpp_class}}::create();
     // FIXME: Do not use Dictionary and DictionaryHelper
     // https://crbug.com/321462
     Dictionary dictionary(v8Value, isolate);
     // FIXME: Remove this v8::TryCatch once the code is switched from
     // Dictionary/DictionaryHelper to something that uses ExceptionState.
     v8::TryCatch block;
     {% for member in members %}
     {{member.cpp_type}} {{member.name}};
     if (DictionaryHelper::getWithUndefinedOrNullCheck(dictionary, "{{member.name}}", {{member.name}})) {
@@ skipping 21 matching lines @@
         v8Object->Set(v8String(isolate, "{{member.name}}"), {{member.cpp_value_to_v8_value}});
     {% if member.v8_default_value %}
     else
         v8Object->Set(v8String(isolate, "{{member.name}}"), {{member.v8_default_value}});
     {% endif %}
     {% endfor %}
     return v8Object;
 }
 
 } // namespace blink