[bindings] Support is_explicit_nullable for method arguments.

Source/bindings/tests/results/core/V8TestObject.cpp

Index: Source/bindings/tests/results/core/V8TestObject.cpp
diff --git a/Source/bindings/tests/results/core/V8TestObject.cpp b/Source/bindings/tests/results/core/V8TestObject.cpp
index aa9558be16a7915839bc4d40ca1bea4e646f4f0d..7235f4e0dbb42a1759ddeaff1a8650f84c0495d2 100644
--- a/Source/bindings/tests/results/core/V8TestObject.cpp
+++ b/Source/bindings/tests/results/core/V8TestObject.cpp
@@ -6215,7 +6215,7 @@ static void voidMethodNullableVoidCallbackFunctionArgMethod(const v8::FunctionCa
         return;
     }
     TestObject* impl = V8TestObject::toImpl(info.Holder());
-    ScriptValue voidCallbackFunctionArg;
+    Nullable<ScriptValue> voidCallbackFunctionArg;

[Jens Widell, 2015/03/02 07:53:13]

This is wrong; ScriptValue can store null, so shouldn't be "explicitly
nullable".

I guess idl_type.is_callback_function is the condition we need to add to
v8_types.cpp_type_has_null_value().

     {
         if (!info[0]->IsFunction() && !info[0]->IsNull()) {
             V8ThrowException::throwTypeError(info.GetIsolate(), ExceptionMessages::failedToExecute("voidMethodNullableVoidCallbackFunctionArg", "TestObject", "The callback provided as parameter 1 is not a function."));