Redirect all mouse input to Alt+Tab window when it's visible,

ash/common/wm/window_cycle_list.cc

Index: ash/common/wm/window_cycle_list.cc
diff --git a/ash/common/wm/window_cycle_list.cc b/ash/common/wm/window_cycle_list.cc
index 70620fbfa0636a83d55f7bafe28a54fbde6c5e1e..0807798230308a1c262a8f933a90c4f312cab8fe 100644
--- a/ash/common/wm/window_cycle_list.cc
+++ b/ash/common/wm/window_cycle_list.cc
@@ -388,6 +388,10 @@ class WindowCycleView : public views::WidgetDelegateView {
     }
   }
 
+  void OnMouseCaptureLost() override {
+    WmShell::Get()->window_cycle_controller()->StopCycling();
+  }
+
   View* GetContentsView() override { return this; }
 
   View* GetInitiallyFocusedView() override {
@@ -595,6 +599,8 @@ void WindowCycleList::InitWindowCycleView() {
   widget_rect.set_height(widget_height);
   widget->SetBounds(widget_rect);
   widget->Show();
+  widget->SetCapture(cycle_view_);
+  widget->set_auto_release_capture(false);
   cycle_ui_widget_.reset(widget);
 }