Remove bogus comments. Note that toJSON is no longer reserved in the spec as of <https://github.com/heycam/webidl/pull/293>. No bug, DONTBUILD.

dom/bindings/parser/WebIDL.py

@@ -367,8 +367,6 @@ class IDLUnresolvedIdentifier(IDLObject):
                               [location])
         if name[0] == '_' and not allowDoubleUnderscore:
             name = name[1:]
-        # TODO: Bug 872377, Restore "toJSON" to below list.
-        # We sometimes need custom serialization, so allow toJSON for now.
         if (name in ["constructor", "toString"] and
             not allowForbidden):
             raise WebIDLError("Cannot use reserved identifier '%s'" % (name),