bindings: Don't throw a TypeError when 'null' is passed to nullable callback function

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 a4fb97619af188d899c3abdbb07e50c4dd40c0f0..d7009da8926ef9d291c860745512eed8fa1bc1c6 100644
--- a/third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl
+++ b/third_party/WebKit/Source/bindings/templates/methods.cpp.tmpl
@@ -177,7 +177,7 @@ if (info.Length() <= {{argument.index}} || !{% if argument.is_nullable %}(info[{
 {% endif %}{# argument.is_optional #}
 {% endif %}{# argument.idl_type == 'EventListener' #}
 {% elif argument.is_callback_function %}
-if (!info[{{argument.index}}]->IsObject() || !v8::Local<v8::Object>::Cast(info[{{argument.index}}])->IsCallable()) {
+if ({% if argument.is_nullable %}!isUndefinedOrNull(info[{{argument.index}}]) && {% endif %}!(info[{{argument.index}}]->IsObject() && v8::Local<v8::Object>::Cast(info[{{argument.index}}])->IsCallable())) {

[peria, 2017/01/05 04:39:18]

who tests this new {% if %} branch in run-binding-test?

[bashi, 2017/01/05 04:41:31]

TestCallbackFunctions.voidMethodNullableCallbackFunctionInArg()

   {{throw_argument_error(method, argument, "The callback provided as parameter %(index)d is not a function.")}}
   return;
 }