GitLab

InitializeSession. This seems to be able to happen if too much time
elapses between the call to the constructor and the call to InitializeSession.

This fixes the fix from https://codereview.chromium.org/560913002

BUG=399147

Review URL: https://codereview.chromium.org/579533003

Cr-Commit-Position: refs/heads/master@{#295601}