Version: 55.0.2883.0 (Official Build) canary 614d31daee2f61b0180df403a8ad43f20b9f6dd7-refs/heads/master@{#423768} (64-bit)
OS: Mac (10.10.5, 10.11.4)

What steps will reproduce the problem?
1) Launch chrome, open NTP, right click and select ‘Inspect’.
2) Click on ‘Customise and control Dev Tools’ button in top corner and undock the Devtools window.
3) Press ‘Ctrl+Cmd+F’ to fullscreen Devtools window.
4) Now again press ‘Ctrl+Cmd+F’ to exit fullscreen and observe the toolbar menu options.

On exiting fullscreen toolbar menu is seen after a delay.

On exiting fullscreen toolbar menu should be seen.

This is a Regression issue broken in M-48, below is the bisect info
Manual bisect:
Good build: 48.0.2560.0
Bad build: 48.0.2561.0

Narrow bisect URL:
https://chromium.googlesource.com/chromium/src/+log/485adb2901e3fcd0adc45ac399c310e1c4a76498..e026f4038aeb0b33904241654375e1a2d1afd9cb?pretty=fuller&n=10000

Suspecting: r358906

Note: Issue is not seen on Windows and Linux OS.

 

Deleted: devtools_actual.mov 4.7 MB

devtools_actual.mov 4.7 MB Download

Deleted: devtools_expected.mov 4.5 MB

devtools_expected.mov 4.5 MB Download