Get rid of custom constructor for FormData

Get rid of custom constructor for FormData

Get rid of custom constructor for FormData and let the generator produces its
code instead. There does not appear to be any difference between the custom
code and the generated one.

R=haraken
TEST=http/tests/local/formdata

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=161498

[Inactive, 2013-11-06 20:57:37]

For comparison, the generated code looks like:
    V8TRYCATCH_VOID(HTMLFormElement*, form,
V8HTMLFormElement::HasInstance(info[0], info.GetIsolate(),
worldType(info.GetIsolate())) ?
V8HTMLFormElement::toNative(v8::Handle<v8::Object>::Cast(info[0])) : 0);

    RefPtr<DOMFormData> impl = DOMFormData::create(form);
    v8::Handle<v8::Object> wrapper = info.Holder();

    V8DOMWrapper::associateObjectWithWrapper<V8FormData>(impl.release(),
&V8FormData::wrapperTypeInfo, wrapper, info.GetIsolate(),
WrapperConfiguration::Dependent);
    info.GetReturnValue().Set(wrapper);

[haraken, 2013-11-07 00:11:06]

LGTM

[commit-bot: I haz the power, 2013-11-07 01:23:47]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ch.dumez@samsung.com/63133002/1

[commit-bot: I haz the power, 2013-11-07 06:23:40]

Change committed as 161498