We might just have to change 
 
  ca_transaction_sync_suppressed_ = translucent;

to 

  ca_transaction_sync_suppressed_ = !IsWindowModalSheet() && translucent;


or add a line at

  if (native_widget_mac_->IsWindowModalSheet()) {
    initial_visibility_suppressed_ = true;
    ShowAsModalSheet();
    return;
  }


(all my mac builds are too old/hosed, so I don't think I'll be able to test this today).

Adding "RBS" label as this is P1 and blocking MacViews launch.

https://chromium-review.googlesource.com/1146136

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4d1f95c1b7779bb4a406d8e22ee0628139999aad

commit 4d1f95c1b7779bb4a406d8e22ee0628139999aad
Author: Trent Apted <tapted@chromium.org>
Date: Mon Jul 23 16:33:42 2018

Mac: Ensure we wait for the first frame for window-modal sheets.

AppKit runs its sheet animation in UI-thread blocking loop. There is no
way to swap in a frame from the compositor while it is running. So
failing to wait means we animate a blank window.

Fix by restoring the wait that regressed in r574771

Test=Bookmark Star -> More...: Ensure the window does not animate in blank.

Bug:  865331 
Change-Id: Ifd87944e3ae0d3af5f5b7eb8569e9a7c98e1be0c
Reviewed-on: https://chromium-review.googlesource.com/1146136
Commit-Queue: ccameron <ccameron@chromium.org>
Reviewed-by: ccameron <ccameron@chromium.org>
Cr-Commit-Position: refs/heads/master@{#577186}
[modify] https://crrev.com/4d1f95c1b7779bb4a406d8e22ee0628139999aad/ui/views/cocoa/bridged_native_widget.mm

Pls request a merge to M69 for CL listed at #5 once change is baked/verified in canary and safe to merge. Thank you.

Tested the issue on Mac 10.13.5 using chrome 69.0.3495.0 build without fix.
After enabling #cocoa at chrome://flags and Edited Bookmark Dialog (bookmark star -> click more)
Observed that same behavior on latest chrome 70.0.3501.0.

Attaching screen cast of fix for reference.

tapted@chromium.org@ - Please find the attached screen-cast and let us know if we have missed anything in the process. Could you please help in verifying the fix.

Thanks...!

Deleted: 865331.mp4 1.2 MB

	865331.mp4 1.2 MB View Download

Requesting merge to m69 for r577186

I see the correct behaviour in 70.0.3501.2. Tested retina and non-retina on 10.13.5 and it is much improved. Screencast attached.

Note there's a timeout when the system is under heavy load so that there isn't an excessive delay before the animation starts - this may be what's observed in #c8

Also there's an issue on 10.10 - filed Issue 867191 - but that's a small portion of users and isn't a regression from the fix here.

Deleted: 3501.mov 1.6 MB

	3501.mov 1.6 MB View Download

Your change meets the bar and is auto-approved for M69. Please go ahead and merge the CL to branch 3497 manually. Please contact milestone owner if you have questions.
Owners: amineer@(Android), kariahda@(iOS), cindyb@(ChromeOS), govind@(Desktop)

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

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9a0eada52918e4c22bd14b48610116d60ae7a060

commit 9a0eada52918e4c22bd14b48610116d60ae7a060
Author: Trent Apted <tapted@chromium.org>
Date: Thu Jul 26 00:36:58 2018

[merge-m69] Mac: Ensure we wait for the first frame for window-modal sheets.

AppKit runs its sheet animation in UI-thread blocking loop. There is no
way to swap in a frame from the compositor while it is running. So
failing to wait means we animate a blank window.

Fix by restoring the wait that regressed in r574771

Test=Bookmark Star -> More...: Ensure the window does not animate in blank.

TBR=tapted@chromium.org

(cherry picked from commit 4d1f95c1b7779bb4a406d8e22ee0628139999aad)

Bug:  865331 
Change-Id: Ifd87944e3ae0d3af5f5b7eb8569e9a7c98e1be0c
Reviewed-on: https://chromium-review.googlesource.com/1146136
Commit-Queue: ccameron <ccameron@chromium.org>
Reviewed-by: ccameron <ccameron@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#577186}
Reviewed-on: https://chromium-review.googlesource.com/1150018
Reviewed-by: Trent Apted <tapted@chromium.org>
Cr-Commit-Position: refs/branch-heads/3497@{#98}
Cr-Branched-From: 271eaf50594eb818c9295dc78d364aea18c82ea8-refs/heads/master@{#576753}
[modify] https://crrev.com/9a0eada52918e4c22bd14b48610116d60ae7a060/ui/views/cocoa/bridged_native_widget.mm

Verified the fix on the latest M-69(69.0.3497.23) on Mac OS 10.13.6. This is working as intended. I was able to repro the issue on the build without fix i.e. on 69.0.3497.12.

Attaching the screen-cast of both actual and expected behavior.

Deleted: 865331_actual.webm 1.4 MB

	865331_actual.webm 1.4 MB View Download

Deleted: 865331_expected.webm 2.0 MB

	865331_expected.webm 2.0 MB View Download