I think we should prioritize this since resolving the constraints breakage takes time and it might delay startup time.

These might have been caused by 
https://chromium-review.googlesource.com/c/chromium/src/+/1141287/13/ios/chrome/browser/ui/tab_grid/tab_grid_view_controller.mm

Error messages:
2018-07-25 17:21:44.379078-0700 Chromium[2398:14139594] [LayoutConstraints] Unable to simultaneously satisfy constraints.
	Probably at least one of the constraints in the following list is one you don't want. 
	Try this: 
		(1) look at each constraint and try to figure out which you don't expect; 
		(2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<NSLayoutConstraint:0x60800029c7a0 recent_tabs_view_controll....width == UIView:0x7f97cdd216b0.width   (active, names: recent_tabs_view_controll...:0x7f97d082f800 )>",
    "<NSLayoutConstraint:0x60800029c890 H:[UIView:0x7f97cdc3d4b0]-(0)-[recent_tabs_view_controll...]   (active, names: recent_tabs_view_controll...:0x7f97d082f800 )>",
    "<NSLayoutConstraint:0x60800029c8e0 recent_tabs_view_controll....trailing == UIView:0x7f97cdc3d4b0.trailing   (active, names: recent_tabs_view_controll...:0x7f97d082f800 )>",
    "<NSLayoutConstraint:0x600000294730 H:[TabGridNewTabButton:0x7f97cdd36580]-(0)-[UIButton:0x7f97cdd2af50]   (active)>",
    "<NSLayoutConstraint:0x6000002943c0 TabGridNewTabButton:0x7f97cdd36580.centerX == UIVisualEffectView:0x7f97cdc43fc0.centerX   (active)>",
    "<NSLayoutConstraint:0x60800029dc90 H:|-(0)-[UIVisualEffectView:0x7f97cdc43fc0]   (active, names: '|':TabGridBottomToolbar:0x7f97cdc3ea20 )>",
    "<NSLayoutConstraint:0x60800029dce0 UIVisualEffectView:0x7f97cdc43fc0.trailing == TabGridBottomToolbar:0x7f97cdc3ea20.trailing   (active)>",
    "<NSLayoutConstraint:0x600000294780 UIButton:0x7f97cdd2af50.trailing == UILayoutGuide:0x6080001b5000'UIViewLayoutMarginsGuide'.trailing   (active)>",
    "<NSLayoutConstraint:0x600000294af0 H:|-(0)-[TabGridBottomToolbar:0x7f97cdc3ea20]   (active, names: '|':UIView:0x7f97cdd216b0 )>",
    "<NSLayoutConstraint:0x600000294b40 TabGridBottomToolbar:0x7f97cdc3ea20.trailing == UIView:0x7f97cdd216b0.trailing   (active)>",
    "<NSLayoutConstraint:0x60800029de70 'UIView-rightMargin-guide-constraint' H:[UILayoutGuide:0x6080001b5000'UIViewLayoutMarginsGuide']-(16)-|(LTR)   (active, names: '|':TabGridBottomToolbar:0x7f97cdc3ea20 )>"
)


Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x600000294730 H:[TabGridNewTabButton:0x7f97cdd36580]-(0)-[UIButton:0x7f97cdd2af50]   (active)>

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
2018-07-25 17:21:44.495486-0700 Chromium[2398:14139594] [LayoutConstraints] Unable to simultaneously satisfy constraints.
	Probably at least one of the constraints in the following list is one you don't want. 
	Try this: 
		(1) look at each constraint and try to figure out which you don't expect; 
		(2) find the code that added the unwanted constraint or constraints and fix it. 
(
    "<NSLayoutConstraint:0x60800029c7a0 recent_tabs_view_controll....width == UIView:0x7f97cdd216b0.width   (active, names: recent_tabs_view_controll...:0x7f97d082f800 )>",
    "<NSLayoutConstraint:0x60800029c890 H:[UIView:0x7f97cdc3d4b0]-(0)-[recent_tabs_view_controll...]   (active, names: recent_tabs_view_controll...:0x7f97d082f800 )>",
    "<NSLayoutConstraint:0x60800029c8e0 recent_tabs_view_controll....trailing == UIView:0x7f97cdc3d4b0.trailing   (active, names: recent_tabs_view_controll...:0x7f97d082f800 )>",
    "<NSLayoutConstraint:0x60c000289ce0 'UIView-Encapsulated-Layout-Width' UIView:0x7f97cdd216b0.width == 375   (active)>"
)