Use dictionaries for context creation attributes. Eliminate custom bindings.

Source/bindings/templates/methods.cpp

 {##############################################################################}
 {% macro generate_method(method, world_suffix) %}
 {% filter conditional(method.conditional_string) %}
 static void {{method.name}}{{method.overload_index}}Method{{world_suffix}}(const v8::FunctionCallbackInfo<v8::Value>& info)
 {
     {# Local variables #}
     {% if method.has_exception_state %}
     ExceptionState exceptionState(ExceptionState::ExecutionContext, "{{method.name}}", "{{interface_name}}", info.Holder(), info.GetIsolate());
     {% endif %}
     {# Overloaded methods have length checked during overload resolution #}
@@ skipping 145 matching lines @@
 {% elif argument.is_variadic_wrapper_type %}
 for (int i = {{argument.index}}; i < info.Length(); ++i) {
     if (!V8{{argument.idl_type}}::hasInstance(info[i], info.GetIsolate())) {
         {{throw_type_error(method, '"parameter %s is not of type \'%s\'."' %
                                    (argument.index + 1, argument.idl_type)) | indent(8)}}
         return;
     }
     {{argument.name}}.append(V8{{argument.idl_type}}::toImpl(v8::Handle<v8::Object>::Cast(info[i])));
 }
 {% elif argument.is_dictionary %}
+{% if not argument.use_permissive_dictionary_conversion %}
 {# Dictionaries must have type Undefined, Null or Object:
 http://heycam.github.io/webidl/#es-dictionary #}
 if (!isUndefinedOrNull(info[{{argument.index}}]) && !info[{{argument.index}}]->IsObject()) {
     {{throw_type_error(method, '"parameter %s (\'%s\') is not an object."' %
                                (argument.index + 1, argument.name)) | indent}}
     return;
 }
+{% endif %}{# not argument.use_permissive_dictionary_conversion #}
 {{argument.v8_value_to_local_cpp_value}};
 {% else %}{# argument.is_nullable #}
 {{argument.v8_value_to_local_cpp_value}};
 {% endif %}{# argument.is_nullable #}
 {# Type checking, possibly throw a TypeError, per:
    http://www.w3.org/TR/WebIDL/#es-type-mapping #}
 {% if argument.has_type_checking_unrestricted %}
 {# Non-finite floating point values (NaN, +Infinity or −Infinity), per:
    http://heycam.github.io/webidl/#es-float
    http://heycam.github.io/webidl/#es-double #}
@@ skipping 462 matching lines @@
     {% filter exposed(method.exposed_test) %}
     {% filter runtime_enabled(method.overloads.runtime_enabled_function_all if method.overloads else method.runtime_enabled_function) %}
     prototypeObject->Set(v8AtomicString(isolate, "{{method.name}}"), v8::FunctionTemplate::New(isolate, {{cpp_class_or_partial}}V8Internal::{{method.name}}MethodCallback, v8Undefined(), defaultSignature, {{method.number_of_required_arguments}})->GetFunction());
     {% endfilter %}
     {% endfilter %}
     {% endfilter %}
     {% endfor %}
     {% endif %}
 }
 {%- endmacro %}