Bug 1510030 - Fix the comment for OpacityBinding::update(). r=gw
Bug 1510030 - Fix the comment for OpacityBinding::update(). r=gw

Differential Revision: https://phabricator.services.mozilla.com/D63601

[ghsync] From https://hg.mozilla.org/mozilla-central/rev/c3e6c17ba7b0cae28b49a99836a5814264fd4825

servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender