DevTools: Fix previously undetected annotation-related issues

R=aandrey, eustas, vsevik
NOTRY=true

Review URL: https://codereview.chromium.org/135253005

git-svn-id: svn://svn.chromium.org/blink/trunk@165836 bbb929c8-8fbe-4397-9dbb-9b2b20218538