Tablet mode DCHECK activating a minimized browser window.

On linux-chromeos ToT @ #613596:
(1) Run chrome --ash-debug-shortcuts
(2) Minimize the browser window
(3) ***optional*** Open a task manager window (Search-Esc)
(4) Enter tablet mode (Ctrl-Alt-Shift-T)
(5) Click on the browser shelf item.
Expected: The browser window shows up
Actual DCHECK (one of two, depending on the option step #3)

If you did perform optional step #3, you'll hit this DCHECK:
[117751:117751:1207/084828.943967:FATAL:window.cc(244)] Check failed: !visible_ || layer()->GetTargetOpacity() > 0.0f. 
#0 0x7f7f8d788bef base::debug::StackTrace::StackTrace()
#1 0x7f7f8d6b7c6b logging::LogMessage::~LogMessage()
#2 0x7f7f88ac350f aura::Window::Show()
#3 0x7f7f876874ed views::NativeWidgetAura::Show()
#4 0x7f7f87669e4e views::Widget::Show()
#5 0x55e9b139a57f BrowserView::Show()
#6 0x55e9b12e7aab ChromeLauncherController::ActivateWindowOrMinimizeIfActive()
#7 0x55e9b150b5c2 BrowserShortcutLauncherItemController::ItemSelected()
#8 0x7f7f8693e92c ash::mojom::ShelfItemDelegateStubDispatch::AcceptWithResponder()

If you did not perform optional step #3, you'll hit this DCHECK:
[138668:138668:1207/090701.819552:FATAL:home_launcher_gesture_handler.cc(647)] Check failed: base::ContainsValue(windows, window_). 
#0 0x7fcd5f416bef base::debug::StackTrace::StackTrace()
#1 0x7fcd5f345c6b logging::LogMessage::~LogMessage()
#2 0x7fcd589f0a79 ash::HomeLauncherGestureHandler::SetUpWindows()
#3 0x7fcd589f2547 ash::HomeLauncherGestureHandler::HideHomeLauncherForWindow()
#4 0x7fcd58c05dfa ash::AnimateShowWindow_SlideDown()
#5 0x7fcd5826c08b wm::VisibilityController::UpdateLayerVisibility()
#6 0x7fcd5a7516f5 aura::Window::SetVisible()
#7 0x7fcd5a75151c aura::Window::Show()
#8 0x7fcd58c02bd5 ash::TabletModeWindowState::UpdateWindow()
#9 0x7fcd58c0f3bf ash::wm::WindowState::OnWindowPropertyChanged()
#10 0x7fcd5a7546d4 aura::Window::AfterPropertyChange()
#11 0x7fcd5f5f48b5 ui::PropertyHandler::SetPropertyInternal()
#12 0x7fcd5a72002a ui::PropertyHandler::SetProperty<>()
#13 0x7fcd5826fa84 wm::Unminimize()
#14 0x7fcd58c18766 ash::WorkspaceLayoutManager::OnWindowActivating()
#15 0x7fcd582683f1 wm::FocusController::SetActiveWindow()
#16 0x7fcd58267238 wm::FocusController::FocusAndActivateWindow()
#17 0x7fcd59315644 views::NativeWidgetAura::Activate()
#18 0x7fcd592d7c1a views::FocusManager::SetFocusedViewWithReason()
#19 0x559508050677 OmniboxViewViews::SetFocus()
#20 0x559508042755 LocationBarView::FocusLocation()
#21 0x55950802fc9a BrowserView::SetFocusToLocationBar()
#22 0x55950802e573 BrowserView::Show()
#23 0x559507f7baab ChromeLauncherController::ActivateWindowOrMinimizeIfActive()
#24 0x55950819f5c2 BrowserShortcutLauncherItemController::ItemSelected()
#25 0x7fcd585cc92c ash::mojom::ShelfItemDelegateStubDispatch::AcceptWithResponder()