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This CL makes all the relevant tracks/capturers to return a feedback
callback upon connection to the source or starting the capture.
The call chain results in VideoCaptureImpl method being plumbed to the
client as a callback.

This is the first step for removing VideoFrameFeedback from the
media::VideoFrame.

Follow-up CLs will introduce the callbacks to mirroring service (which is
a second user of feedback mechanism) and would remove VideoFrameFeedback
member from media::VideoFrame.

Bug: chromium:1134073
Change-Id: I61dfc8449e69ad53f3fc6610d8cfbf4cdb6e4441
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2489644
Commit-Queue: Ilya Nikolaevskiy <ilnik@chromium.org>
Reviewed-by: Guido Urdaneta <guidou@chromium.org>
Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Auto-Submit: Ilya Nikolaevskiy <ilnik@chromium.org>
Cr-Commit-Position: refs/heads/master@{#825316}