Revert "Add callback to copy texture backed frames in WebRtcVideoFrameAdapter"

This CL reverts the commit on https://codereview.chromium.org/2456443002. We found
that this can cause a deadlock because of the dependency between threads, see the
bug for details. Instead of copying texture content, we generate a black frame.

Bug: 663452
Change-Id: Ifb2195cbf123dde8a8f9260d606a28df26b39121
Reviewed-on: https://chromium-review.googlesource.com/900663
Reviewed-by: Christian Fremerey <chfremer@chromium.org>
Reviewed-by: Magnus Jedvert <magjed@chromium.org>
Commit-Queue: Emircan Uysaler <emircan@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#535529}(cherry picked from commit 03970a908a4ff71f39147348b13b0dde37a11787)
Reviewed-on: https://chromium-review.googlesource.com/941502
Reviewed-by: Emircan Uysaler <emircan@chromium.org>
Cr-Commit-Position: refs/branch-heads/3325@{#625}
Cr-Branched-From: bc084a8b5afa3744a74927344e304c02ae54189f-refs/heads/master@{#530369}
6 files changed