commit be152f5f9e9106bb3f33be8cb794761ed76c1297
author Erik Språng <sprang@webrtc.org> Mon Apr 06 14:30:23 2020
committer Commit Bot <commit-bot@chromium.org> Mon Apr 06 15:34:58 2020
tree 477c07c7029c89de5299c806dd33de574023b95b
parent d339bde338c1ae5049dadee1aa8a8ff640223c65

Optimizes thread usage with task queue pacer.

The TaskQueuePacedSender today has some inefficiencies:
* Enqueuing a packet will trigger a MaybeProcessPackets() call, but it
  won't actually run immediately even if it should - instead it will
  schedule a new call in at least 1ms. This incurs delays and extra
  CPU overhead.
* Sometimes thread wakeups are scheduled simply in order to do
  book-keeping: ProcessPackets() will be called when the media debt has
  gone down to 0 even if there is no packet in the queue, in order to
  check if we should send padding.

This CL fixes that by called ProcessPackets() immediately if it is
actually time to do so, and by immediately determining when padding
should be sent without having a separate call to drain media debt.

Bug: webrtc:10809
Change-Id: I4870e86e6de2ce4197463fd5b788ad4717fc7177
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/172842
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#31010}