GitLab

Rename elapsed-time field in Chromoting log events to session-duration, and record time in seconds, to align with server-side field names and units.

BUG=461610
Tested by running run_webapp_unittest.py with these changes; all tests passed.

Review URL: https://codereview.chromium.org/961053004

Cr-Commit-Position: refs/heads/master@{#319200}