Keep the SystemModalContainerEventHandler added

components/exo/touch.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/exo/touch.h"
 
 #include "ash/shell.h"
 #include "components/exo/surface.h"
 #include "components/exo/touch_delegate.h"
 #include "ui/aura/window.h"
@@ skipping 28 matching lines @@
   delegate_->OnTouchDestroying(this);
   if (focus_)
     focus_->RemoveSurfaceObserver(this);
   ash::Shell::GetInstance()->RemovePreTargetHandler(this);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // ui::EventHandler overrides:
 
 void Touch::OnTouchEvent(ui::TouchEvent* event) {
+  if (!ash::Shell::GetInstance()->CanWindowReceiveEvents(
+          (aura::Window*)event->target())) {
+    event->StopPropagation();
+    return;
+  }
+
   switch (event->type()) {
     case ui::ET_TOUCH_PRESSED: {
       // Early out if event doesn't contain a valid target for touch device.
       Surface* target = GetEffectiveTargetForEvent(event);
       if (!target)
         return;
 
       // If this is the first touch point then target becomes the focus surface
       // until all touch points have been released.
       if (touch_points_.empty()) {
@@ skipping 83 matching lines @@
 Surface* Touch::GetEffectiveTargetForEvent(ui::Event* event) const {
   Surface* target =
       Surface::AsSurface(static_cast<aura::Window*>(event->target()));
   if (!target)
     return nullptr;
 
   return delegate_->CanAcceptTouchEventsForSurface(target) ? target : nullptr;
 }
 
 }  // namespace exo