IDL parser: override Attribute production from base IDL parser

The Attribute production is deprecated in the base IDL parser and is kept
around only because Blink references it.

It would be better to name this production ExceptionAttribute, but doing
that now leaves the Attribute production in the base parser unused, which
causes warnings. Overriding it here will let us remove it from the base
parser without fuzz.

Review URL: https://codereview.chromium.org/793343002

git-svn-id: svn://svn.chromium.org/blink/trunk@186957 bbb929c8-8fbe-4397-9dbb-9b2b20218538
1 file changed