Properly handle parsing a '%'-prefixed runtime call as a binding pattern

Properly handle parsing a '%'-prefixed runtime call as a binding pattern

R=rossberg@chromium.org
BUG=chromium:552302
LOG=n

Committed: https://crrev.com/9a8c0119efb243cfd1400dcd160cda20ac5157c3
Cr-Commit-Position: refs/heads/master@{#31890}

[rossberg, 2015-11-09 13:26:52]

lgtm

[adamk, 2015-11-09 15:15:09]

The CQ bit was checked by adamk@chromium.org

[commit-bot: I haz the power, 2015-11-09 15:15:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1425723004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1425723004/1

[commit-bot: I haz the power, 2015-11-09 15:32:07]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-09 15:32:38]

Patchset 1 (id:??) landed as
https://crrev.com/9a8c0119efb243cfd1400dcd160cda20ac5157c3
Cr-Commit-Position: refs/heads/master@{#31890}