Affects landscape only. M63.

We should probably fix this, but still lowering to Pri-3 because rotating 180º sidesteps the issue. 

Hey kkhorimoto@@ are you looking into this issue?

I can take a look, but I wasn't prioritizing stack view polish bugs since we're planning to replace it with the new tab switcher shortly.  This is a little ugly though, so I'll try to fix sooner.

Changing slightly the constraints added in https://chromium-review.googlesource.com/c/chromium/src/+/741599/2/ios/chrome/browser/ui/stack_view/stack_view_controller.mm may solve this bug.

It does solve this bug, but then it breaks the presentation/dismissal animation of the StackView.

FWIW, the constraints that respect the safe area would be:

    UILayoutGuide* safeAreaLayoutGuide = SafeAreaLayoutGuideForView(self.view);
    [NSLayoutConstraint activateConstraints:@[
      [_scrollView.topAnchor
          constraintEqualToAnchor:[_toolbarController view].bottomAnchor],
      [_scrollView.leadingAnchor
          constraintEqualToAnchor:safeAreaLayoutGuide.leadingAnchor],
      [_scrollView.trailingAnchor
          constraintEqualToAnchor:safeAreaLayoutGuide.trailingAnchor],
      [_scrollView.bottomAnchor constraintEqualToAnchor:safeAreaLayoutGuide.bottomAnchor]
    ]];

I went ahead and added this bug reference to your CL (reviewing it now).  Could you create another bug describing the bugs that this introduces?  Thanks!

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/c28e695161d2e3db018dd78c1d0b743439e1a4d8

commit c28e695161d2e3db018dd78c1d0b743439e1a4d8
Author: Jean-François Geyelin <jif@chromium.org>
Date: Fri Oct 27 18:53:14 2017

Have the StackView's scrollview be positioned with autolayout.

Bug:  779032 ,  765408 
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet
Change-Id: I6731b515f1ae2e7f33dde48f9f4ab84334af530b
Reviewed-on: https://chromium-review.googlesource.com/741599
Reviewed-by: Kurt Horimoto <kkhorimoto@chromium.org>
Commit-Queue: Kurt Horimoto <kkhorimoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#512256}
[modify] https://crrev.com/c28e695161d2e3db018dd78c1d0b743439e1a4d8/ios/chrome/browser/ui/stack_view/stack_view_controller.mm

Haven't created a separate bug because I think the animation should be updated at the same time that the constraints are updated.

mardini@ I recommend we WontFix -- the stack view is getting replaced soonish and this doesn't obscure functionality.  So far my informal straw poll has everyone leaning towards WontFix -- do you have a preference?

I agree. Thanks for checking.