[ak] Pub setup to build with stable rather than bleeding edge
[ak] Null guard a couple of places where we seem to have a race condition with shadowRoot
[ak] Even better, let's just ignore the exceptions
Null guard a couple of places where we seem to have a race condition with shadowRoot

BUG=
R=kevmoo@google.com

Review URL: https://codereview.chromium.org//247803002
[ak] Merged