This was caused by https://chromium-review.googlesource.com/c/chromium/src/+/1011343 since BrowserActionsContainer::GetWidth() now clamps down to 0, rather than `toolbar_actions_bar_->GetMinimumWidth()`. 

As a result, in ToolbarActionsBar::ResizeDelegate() [1] which is called from ToolbarActionsBar::OnToolbarActionAdded() [2], the desired_width is 0 (since the omnibox was resized so that extension moves to the menu before the extension was disabled and reenabled). BrowserActionsContainer::GetWidth() returns 0 as well, so we endup calling `delegate_->Redraw(false);` rather than calling `delegate_->ResizeAndAnimate(tween_type, desired_width);`

Clamping down to `toolbar_actions_bar_->GetMinimumWidth()` fixes the problem. But I'm not sure if that works for the recently added separator area work. pbos@ can you please take a look?

[1]: https://cs.chromium.org/chromium/src/chrome/browser/ui/toolbar/toolbar_actions_bar.cc?type=cs&q=ToolbarActionsBar::ResizeDelegate&sq=package:chromium&l=687

[2]: https://cs.chromium.org/chromium/src/chrome/browser/ui/toolbar/toolbar_actions_bar.cc?type=cs&q=ToolbarActionsBar::OnToolbarActionAdded&sq=package:chromium&l=609

At a glance I think it should be fine, but this will break returning zero when width() does, so maybe we need to special case that if we need to handle the too-tiny-for-resize-handle case. WDYT?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/95bff1bfd712ccb5f7ad4bfdeaf4ceb26ad0aedf

commit 95bff1bfd712ccb5f7ad4bfdeaf4ceb26ad0aedf
Author: Peter Boström <pbos@chromium.org>
Date: Fri Apr 27 00:07:01 2018

Clamp BrowserActionsContainer::GetWidth()

This fixes an issue where the browser actions bar disappears after
disabling the last extension (intended) and cannot come. Before this
change when re-enabling an extension the bar would not be resized to
include its resize handle so it could not be pulled to bring out the
newly added extension.

The fix seems fairly safe which is good as it needs to be merged into
M67. I'm intending to revisit this part of the code as part of cleanup
work to unify ToolbarActionsBar and BrowserActionsContainer.

Bug:  chromium:836182 
Change-Id: I2a196edc867ec70dd74aa4690576540b31548b97
Reviewed-on: https://chromium-review.googlesource.com/1030891
Commit-Queue: Peter Boström <pbos@chromium.org>
Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#554202}
[modify] https://crrev.com/95bff1bfd712ccb5f7ad4bfdeaf4ceb26ad0aedf/chrome/browser/ui/views/toolbar/browser_actions_container.cc

Rechecked the above issue on latest Canary build #68.0.3410.0 for Windows OS (7, 8, 8.1, 10) and Linux OS (14.04 LTS) and the issue is fixed.
Please refer the attached screencast.

Deleted: Fixed Video.mp4 466 KB

	Fixed Video.mp4 466 KB View Download

Thank you!

Additional info for merge request: Without this fix the browser actions will be invisible and unusable when going from zero enabled to more extensions. It's pretty user visible and feels very broken.

Approving merge to M67 branch 3396 based on comment #4 and #6. Please merge ASAP. Thank you.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/660c34994165eea303bd6f4bf6254be642786111

commit 660c34994165eea303bd6f4bf6254be642786111
Author: Peter Boström <pbos@chromium.org>
Date: Fri Apr 27 18:35:17 2018

Clamp BrowserActionsContainer::GetWidth()

This fixes an issue where the browser actions bar disappears after
disabling the last extension (intended) and cannot come. Before this
change when re-enabling an extension the bar would not be resized to
include its resize handle so it could not be pulled to bring out the
newly added extension.

The fix seems fairly safe which is good as it needs to be merged into
M67. I'm intending to revisit this part of the code as part of cleanup
work to unify ToolbarActionsBar and BrowserActionsContainer.

Bug:  chromium:836182 
Change-Id: I2a196edc867ec70dd74aa4690576540b31548b97
Reviewed-on: https://chromium-review.googlesource.com/1030891
Commit-Queue: Peter Boström <pbos@chromium.org>
Reviewed-by: Bret Sepulveda <bsep@chromium.org>
Reviewed-by: Ahmed Fakhry <afakhry@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#554202}(cherry picked from commit 95bff1bfd712ccb5f7ad4bfdeaf4ceb26ad0aedf)
Reviewed-on: https://chromium-review.googlesource.com/1033395
Reviewed-by: Peter Boström <pbos@chromium.org>
Cr-Commit-Position: refs/branch-heads/3396@{#355}
Cr-Branched-From: 9ef2aa869bc7bc0c089e255d698cca6e47d6b038-refs/heads/master@{#550428}
[modify] https://crrev.com/660c34994165eea303bd6f4bf6254be642786111/chrome/browser/ui/views/toolbar/browser_actions_container.cc

Verified by TE in #4

Tested this issue on Windows 10,Debian Rodate using chrome-67.0.3396.30  & seems issue working as intended as per C#0.

Hence adding TE verified labels.Please find the attached screencast for reference.

Thanks..!

Deleted: 836182-Win.mp4 847 KB

	836182-Win.mp4 847 KB View Download