[Notifications] Drop tap gestures for ArcCustomNotificationView.

ui/arc/notification/arc_custom_notification_view.cc

 // Copyright 2016 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 "ui/arc/notification/arc_custom_notification_view.h"
 
 #include "ash/wm/window_util.h"
 #include "base/auto_reset.h"
 #include "base/memory/ptr_util.h"
 #include "components/exo/notification_surface.h"
@@ skipping 30 matching lines @@
     if (owner_->floating_control_buttons_widget_ && event->target() &&
         owner_->floating_control_buttons_widget_->GetNativeWindow() ==
             event->target()) {
       return;
     }
 
     if (event->IsScrollEvent()) {
       ForwardScrollEvent(event->AsScrollEvent());
     } else if (event->IsMouseWheelEvent()) {
       ForwardMouseWheelEvent(event->AsMouseWheelEvent());
-    } else if (!event->IsTouchEvent()) {
+    } else if (!event->IsTouchEvent() && event->type() != ui::ET_GESTURE_TAP) {
       // TODO(yoshiki): Use a better tigger (eg. focusing EditText on
       // notification) than clicking (crbug.com/697379).
       if (event->type() == ui::ET_MOUSE_PRESSED)
         owner_->ActivateToast();
 
-      // Forward the rest events to |owner_| except touches because View
-      // should no longer receive touch events. See View::OnTouchEvent.
+      // Forward the rest events to |owner_| except for:
+      // 1. Touches, because View should no longer receive touch events.
+      //    See View::OnTouchEvent.
+      // 2. Tap gestures are handled on the Android side, so ignore them.
+      //    See crbug.com/709911.
       owner_->OnEvent(event);
     }
   }
 
   void ForwardScrollEvent(ui::ScrollEvent* event) {
     views::Widget* widget = owner_->GetWidget();
     if (!widget)
       return;
 
     event->target()->ConvertEventToTarget(widget->GetNativeWindow(), event);
@@ skipping 548 matching lines @@
 
 void ArcCustomNotificationView::OnNotificationSurfaceRemoved(
     exo::NotificationSurface* surface) {
   if (surface->notification_id() != notification_key_)
     return;
 
   SetSurface(nullptr);
 }
 
 }  // namespace arc