You are probably looking for a change made after 504965 (known good), but no later than 504966 (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/41ed4a4682284e379929281189ede6a9e13a1fb4..46fb5c855a8622fe73a5c8000b7370407b9122af

Suspect: https://chromium.googlesource.com/chromium/src/+/46fb5c855a8622fe73a5c8000b7370407b9122af

@beccahughes: 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.

The menu is positioned wrongly in the expected video too so I don't think the range is valid here. @mlamouri - could this have something to do with your menu positioning change?

The flickering is definitely something that was introduced with your CL, though, as you pointed, the position is off so if I can find the flickering source at the same time, I will fix both.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/db17c3ccab2dbe2ce85e2317c26f7104570ec28e

commit db17c3ccab2dbe2ce85e2317c26f7104570ec28e
Author: Mounir Lamouri <mlamouri@chromium.org>
Date: Tue Oct 24 15:25:42 2017

Media Controls: add "px" to media controls popup menu rule to position.

Otherwise, depending on the element for which the popup menu is created,
the position might be off.

Bug:  777278 
Change-Id: I2e5ffbc08ffa88997a42a3ee09d0dec65798c097
Reviewed-on: https://chromium-review.googlesource.com/735611
Reviewed-by: Becca Hughes <beccahughes@chromium.org>
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/heads/master@{#511155}
[modify] https://crrev.com/db17c3ccab2dbe2ce85e2317c26f7104570ec28e/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.cpp

Rechecked this issue on Windows 10 64.0.3249.2 Canary and 64.0.3249.0 Canary for Mac 10.12.6 & Ubuntu 14.04, fix is working as intended. No Flickering of CC menu is observed after playing video

Adding TE-Verified labels for M64

Your change meets the bar and is auto-approved for M63. Please go ahead and merge the CL to branch 3239 manually. Please contact milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), gkihumba@(ChromeOS), govind@(Desktop)

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

Please merge your change to M63 branch 3239 by 4:00 PM PT, tomorrow (Wednesday). Thank you.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fb819a8cf0df220a3e9a4405e23a7fc5afe358ac

commit fb819a8cf0df220a3e9a4405e23a7fc5afe358ac
Author: Mounir Lamouri <mlamouri@chromium.org>
Date: Thu Oct 26 10:15:39 2017

Media Controls: add "px" to media controls popup menu rule to position.

Otherwise, depending on the element for which the popup menu is created,
the position might be off.

TBR=mlamouri@chromium.org

(cherry picked from commit db17c3ccab2dbe2ce85e2317c26f7104570ec28e)

Bug:  777278 
Change-Id: I2e5ffbc08ffa88997a42a3ee09d0dec65798c097
Reviewed-on: https://chromium-review.googlesource.com/735611
Reviewed-by: Becca Hughes <beccahughes@chromium.org>
Commit-Queue: Mounir Lamouri <mlamouri@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#511155}
Reviewed-on: https://chromium-review.googlesource.com/737998
Reviewed-by: Mounir Lamouri <mlamouri@chromium.org>
Cr-Commit-Position: refs/branch-heads/3239@{#236}
Cr-Branched-From: adb61db19020ed8ecee5e91b1a0ea4c924ae2988-refs/heads/master@{#508578}
[modify] https://crrev.com/fb819a8cf0df220a3e9a4405e23a7fc5afe358ac/third_party/WebKit/Source/modules/media_controls/MediaControlsImpl.cpp

Retested above issue on Windows(7,8,10), Mac(10.12.6) & Linux (14.04 LTS) OS using Beta #63.0.3239.30 build and issue is fixed. Kindly review an attached video.

Deleted: Fixed Video.mov 2.4 MB

Fixed Video.mov 2.4 MB Download