Correction: This is a regression issue and broken in M-57 series.

Below is manual regression range.

Good build: 57.0.2978.0  
Bad build: 57.0.2979.0

Note: 
1. Video is rendering properly in full-screen mode on Firefox browser.
2. Issue is reproducible on Mac and Linux OS also.

Kindly review the attached screen-cast for reference.

Using the per-revision bisect providing the bisect results,
Good Build 57.0.2978.0 (revision : 442756) 
Bad Build  57.0.2979.0 (revision : 443120)

You are probably looking for a change made after 443055 (known good), but no lat
er than 443056 (first known bad).
CHANGELOG URL:
The script might not always return single CL as suspect as some perf builds might get missing due to failure.
  https://chromium.googlesource.com/chromium/src/+log/ff407634505cc3c6203ed2f746000b6d6eea79b6..513f1f02c5c928367006c600cd1098f6315654ca

From the CL above, assigning the issue to the concern owner 

cbiesinger@ - Could you please check whether this is caused with respect to your change, if not please help us in assigning it to the right owner.

Review-Url: https://codereview.chromium.org/2624143005

Thanks..

Adding ReleaseBlock-stable as this is recent regression. Please feel free to edit or delete.

Thanks..

cbiesinger@@ Gentle Ping! Since this issue is marked as RB-Stable can we get any update on this issue?

Thanks!

Should also be fixed by https://codereview.chromium.org/2684463002/. Since this testcase is pretty different, I will not mark it as a duplicate.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/3c12965b9c068f00290a4c4ecce1cc9d404ec20a

commit 3c12965b9c068f00290a4c4ecce1cc9d404ec20a
Author: cbiesinger <cbiesinger@chromium.org>
Date: Tue Feb 07 20:03:27 2017

[css-flexbox] Clear override sizes when we're no longer a flex item

When we change to being absolutely positioned, we need to clear the override
size so as to avoid being affected by it.

R=eae@chromium.org
BUG= 687747 , 688938 , 688253 

Review-Url: https://codereview.chromium.org/2684463002
Cr-Commit-Position: refs/heads/master@{#448709}

[add] https://crrev.com/3c12965b9c068f00290a4c4ecce1cc9d404ec20a/third_party/WebKit/LayoutTests/css3/flexbox/change-flexitem-into-abspos.html
[modify] https://crrev.com/3c12965b9c068f00290a4c4ecce1cc9d404ec20a/third_party/WebKit/Source/core/layout/LayoutBox.cpp

Your change meets the bar and is auto-approved for M57. Please go ahead and merge the CL to branch 2987 manually. Please contact milestone owner if you have questions.
Owners: amineer@(clank), cmasso@(bling), ketakid@(cros), govind@(desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Tested on Win7 / 58.0.3006.0 (Official Build) canary (64-bit).
Video is rendering/playing properly in full-screen mode.
If possible, could you please merge your change to M57 branch 2987 before 5:00 PM PT today, Wednessday (02/08/17). thank you.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/986dbbcbd724c5fb503b26ca44bec5b68dc3a88a

commit 986dbbcbd724c5fb503b26ca44bec5b68dc3a88a
Author: Christian Biesinger <cbiesinger@chromium.org>
Date: Wed Feb 08 21:14:43 2017

[css-flexbox] Clear override sizes when we're no longer a flex item

When we change to being absolutely positioned, we need to clear the override
size so as to avoid being affected by it.

R=eae@chromium.org
BUG= 687747 , 688938 , 688253 

Review-Url: https://codereview.chromium.org/2684463002
Cr-Commit-Position: refs/heads/master@{#448709}
(cherry picked from commit 3c12965b9c068f00290a4c4ecce1cc9d404ec20a)

Review-Url: https://codereview.chromium.org/2684073004 .
Cr-Commit-Position: refs/branch-heads/2987@{#395}
Cr-Branched-From: ad51088c0e8776e8dcd963dbe752c4035ba6dab6-refs/heads/master@{#444943}

[add] https://crrev.com/986dbbcbd724c5fb503b26ca44bec5b68dc3a88a/third_party/WebKit/LayoutTests/css3/flexbox/change-flexitem-into-abspos.html
[modify] https://crrev.com/986dbbcbd724c5fb503b26ca44bec5b68dc3a88a/third_party/WebKit/Source/core/layout/LayoutBox.cpp

Verified the fix on Mac 10.12.2, Win-10 and Ubuntu 14.04 using Chrome beta version #57.0.2987.54 as per the comment #0.

Observed that video rendered properly in full-screen mode without any issues as expected.

Hence, the fix is working as expected.

Attaching the screencast for reference

Adding the verified labels.

Thanks...!!

Deleted: 688253.mp4 5.4 MB

	688253.mp4 5.4 MB View Download