WIP bindings: Expand usage of NativeValueTraits.

third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl

Index: third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl
diff --git a/third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl b/third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl
index 212b495db59cbeded62532ba0ee5dc4ed810f360..8941adc9ead35c67694dddffdb47a4403032a00d 100644
--- a/third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl
+++ b/third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl
@@ -6,19 +6,13 @@ static void {{method.name}}{{method.overload_index}}Method{{world_suffix}}(const
   {% filter format_remove_duplicates([
       'ExceptionState exceptionState',
       'ScriptState* scriptState = ']) %}
-  {% set define_exception_state -%}
   ExceptionState exceptionState(info.GetIsolate(), ExceptionState::ExecutionContext, "{{interface_name}}", "{{method.name}}");
-  {%- endset %}
 
   {% set function_call = func_call_with_prep_of_args(method, world_suffix) %}
 
-  {% if 'exceptionState' in function_call or
-        (method.returns_promise and not method.is_static) %}
-  {{define_exception_state}}
   {% if method.returns_promise %}
   ExceptionToRejectPromiseScope rejectPromiseScope(info, exceptionState);
   {% endif %}
-  {% endif %}
 
   {% if not method.is_static %}
   {% if method.returns_promise %}
@@ -35,13 +29,12 @@ static void {{method.name}}{{method.overload_index}}Method{{world_suffix}}(const
   // here.
   LocalDOMWindow* impl = toLocalDOMWindow({{v8_class}}::toImpl(info.Holder()));
   {% else %}
-  {{cpp_class}}* impl = {{v8_class}}::toImpl(info.Holder());
+  {{cpp_class}}* impl = NativeValueTraits<{{cpp_class}}>::nativeValue(info.GetIsolate(), info.Holder(), exceptionState);
   {% endif %}{# interface_name == 'Window' and not method.is_cross_origin #}
   {% endif %}{# not method.is_static #}
 
   {# Security checks #}
   {% if method.is_check_security_for_return_value %}
-  {{define_exception_state}}
   if (!BindingSecurity::shouldAllowAccessTo(currentDOMWindow(info.GetIsolate()), {{method.cpp_value}}, exceptionState)) {
     v8SetReturnValueNull(info);
     return;