The timestamps returned by the clocks do not have an epoch. Each clock
should be able to convert a timestamp it returns to an NTP time.
The default implementation for querying for an NTP time is converting
the current timestamp.
This is favored over returning the offset between the relative and the
NTP time because there is a field trial that makes the real clock revert
to using system dependent methods for getting the NTP time.
Bug: webrtc:11327
Change-Id: Ia139b2744b407cae94420bf9112212ec577efb16
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/219687
Reviewed-by: Minyue Li <minyue@webrtc.org>
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Paul Hallak <phallak@google.com>
Cr-Commit-Position: refs/heads/master@{#34071}