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Problem:

CL:2010243 made it so that the GL image for a video frame is created
using the visible size. This is correct because we want to make sure
that when we composite, we don't sample padding (which would result in
unwelcome green lines). However, the coded size of the video frame sent
to the client still contained the non-visible area. This caused
PaintCanvasVideoRenderer to sometimes issue GL commands with dimensions
exceeding those of the GL image backing the texture. These commands
would subsequently fail validation resulting in the associated video
frame not being rendered on the canvas.

Solution:

This CL is a generalization of CL:2056285 which solved the same problem
but for the VA-API video decode accelerator. The essence of the solution
here is to override ProvidePictureBuffersWithVisibleRect() in
VdaVideoDecoder. That way, we end up creating the outgoing video frame
with a coded size equal to the visible size solving the problem above.

Note that there's one caveat: there is an unusual corner case where an
H.264 video includes information about a visible rectangle whose origin
is not at (0, 0). Therefore some of the top and left parts of the video
should not be displayed. However, Chrome does not currently deal well
with this case. This CL does not make that situation better, but this
could be addressed in a follow-up CL considering that it's a rare case.

I tested across many boards. To see the test cases and screenshots of
the results, see [1] (a d08cb982 in the filename represents the base
commit before this CL).

[1] https://drive.google.com/open?id=1h94xbzNLBrlHBlbmaaasHV1P7HOaPBt1

Bug: 1062002
Test: video in bug gets rendered to canvas in kevin successfully.
Change-Id: I6daf9df07c8588d82d5396908d8f91c92ce3984d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2122484
Commit-Queue: Andres Calderon Jaramillo <andrescj@chromium.org>
Reviewed-by: Alexandre Courbot <acourbot@chromium.org>
Reviewed-by: Dan Sanders <sandersd@chromium.org>
Cr-Commit-Position: refs/heads/master@{#754840}