V8 exception lost

R=jacobr@google.com
TBR=alanknight@google.com, jacobr@gogle.com

Review URL: https://codereview.chromium.org/1692753003 .

git-svn-id: https://src.chromium.org/blink/branches/dart/2454_1@202777 bbb929c8-8fbe-4397-9dbb-9b2b20218538
1 file changed