I am also having this problem. The main thing is that the entire content window freezes while the animation is playing, including fullscreen youtube video.

Any chance to fix this for M59 since this worked fine in 10.11.x and is now broken in 10.12.x?

Thank you. 

Working on it

Great, thank you very much. 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/34fe593135e5c15e0660fca8a86b5dbd960e3255

commit 34fe593135e5c15e0660fca8a86b5dbd960e3255
Author: spqchan <spqchan@chromium.org>
Date: Wed Apr 26 17:47:08 2017

[Mac] Fullscreen Toolbar Janky Animation Fix

The browser UI doesn't update when the menubar is being revealed in 10.12+
which makes the toolbar janky. To smooth things out, we should animate
the toolbar in and out.

BUG= 672254 

Review-Url: https://codereview.chromium.org/2827383004
Cr-Commit-Position: refs/heads/master@{#467368}

[modify] https://crrev.com/34fe593135e5c15e0660fca8a86b5dbd960e3255/chrome/browser/ui/cocoa/fullscreen/fullscreen_menubar_tracker.mm

spqchan@: The hide in/out animation of the Menubar in Fullscreen Mode looks and feels smooth again in macOS 10.12.5 with latest Canary Version 61.0.3155.0. I think has been fixed by your comment 7 in  issue 732952 . Thanks :-)

It's still kind of out of sync with the menu bar for me, and there's no animation when the toolbar is hidden. Attaching a screen recording in case it's different from what you see.

Deleted: crbug_672254_toolbar_animation.mp4 306 KB

	crbug_672254_toolbar_animation.mp4 306 KB View Download

Not an easy thing to fix because the browser UI doesn't draw when the menu bar animates

sdy@: Yes, you're right. Comparing Stable with Canary you'll notice that is a bit better now in Canary.

Here are two screencast Stable vs Canary.

Deleted: Chrome_Stable_59.0.3071.115.mov 1.1 MB

Chrome_Stable_59.0.3071.115.mov 1.1 MB Download

Deleted: Chrome_Canary_61.0.3155.0.mov 1.5 MB

Chrome_Canary_61.0.3155.0.mov 1.5 MB Download

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/2c0dbb478638cebb3606d74a69696e63d62529bd

commit 2c0dbb478638cebb3606d74a69696e63d62529bd
Author: Sidney San Martín <sdy@chromium.org>
Date: Tue Jul 25 17:46:09 2017

Call +[CATransaction flush] for the toolbar to move with the menu bar.

Bug:  672254 
Change-Id: I1f6a8a6e0cc5437a67703650732b3ed12c785351
Reviewed-on: https://chromium-review.googlesource.com/581859
Commit-Queue: Sidney San Martin <sdy@chromium.org>
Reviewed-by: Trent Apted <tapted@chromium.org>
Reviewed-by: Sarah Chan <spqchan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#489358}
[modify] https://crrev.com/2c0dbb478638cebb3606d74a69696e63d62529bd/chrome/browser/ui/cocoa/fullscreen/fullscreen_menubar_tracker.mm

Thanks sdy@. Looks good in Chrome Canary Version 62.0.3167.0 on macOS 10.12.6.

(Removing OS=Chrome label. This issue is macOS-only.)