Reland "Passing audio capture timestamp to WebRTC."

This is a reland of 00134099e5c5f06d0f4a085e7c45cc9b1b938adf

Original change's description:
> Passing audio capture timestamp to WebRTC.
> 
> Bug: 1054403
> Change-Id: I6349687ce55535a0cdc405db67687d967a04fea1
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2066777
> Commit-Queue: Minyue Li <minyue@chromium.org>
> Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
> Reviewed-by: Guido Urdaneta <guidou@chromium.org>
> Reviewed-by: Henrik Andreasson <henrika@chromium.org>
> Reviewed-by: Yuri Wiitala <miu@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#749126}

Bug: 1054403
Change-Id: Icf0af14fd91f2390c933d4b97b8cdbe06dc34ada
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2093446
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Commit-Queue: Minyue Li <minyue@chromium.org>
Cr-Commit-Position: refs/heads/master@{#749332}