IDL: Add missing type-check for callback function arguments

IDL: Add missing type-check for callback function arguments

Internally, callback function arguments are represented as ScriptValue
and can thus support any value, but the bindings layer should throw
a TypeError if the value isn't a function object.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=188611

[Jens Widell, 2015-01-19 08:19:28]

jl@opera.com changed reviewers:
+ haraken@chromium.org

[Jens Widell, 2015-01-19 08:19:29]

PTAL

This change currently only affects setTimeout/setInterval, where the missing
type-checks isn't a problem, since those methods are overloaded on the argument
in question, meaning the type is in practice checked as part of the overload
resolution.

[haraken, 2015-01-19 08:25:32]

LGTM

[Jens Widell, 2015-01-19 08:26:35]

The CQ bit was checked by jl@opera.com

[commit-bot: I haz the power, 2015-01-19 08:27:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/810563007/1

[commit-bot: I haz the power, 2015-01-19 09:42:28]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=188611