Mash: Fix and enable ChromeOSInfoPrivateTest.StylusSeen

Bug: 814675
Change-Id: I0eef36c50c2ec3b6dcc5566e553ed26f27379528
Reviewed-on: https://chromium-review.googlesource.com/c/1311657Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Evan Stade <estade@chromium.org>
Cr-Commit-Position: refs/heads/master@{#604586}

chrome/browser/chromeos/extensions/info_private_apitest.cc

@@ -21,6 +21,7 @@
 #include "components/arc/arc_util.h"
 #include "components/prefs/pref_service.h"
 #include "services/ws/public/cpp/input_devices/input_device_client_test_api.h"
+#include "ui/base/ui_base_features.h"
 #include "ui/events/devices/input_device.h"
 #include "ui/events/devices/touchscreen_device.h"
 #include "ui/events/test/event_generator.h"
@@ -188,7 +189,10 @@ IN_PROC_BROWSER_TEST_F(ChromeOSInfoPrivateTest, StylusSeen) {
   touchscreen.has_stylus = true;
   test_api.SetTouchscreenDevices({touchscreen});
 
-  ui::test::EventGenerator generator(browser()->window()->GetNativeWindow());
+  ui::test::EventGenerator generator(
+      features::IsUsingWindowService()
+          ? nullptr
+          : browser()->window()->GetNativeWindow());
   generator.EnterPenPointerMode();
   generator.PressTouch();
   generator.ReleaseTouch();

testing/buildbot/filters/chromeos.mash.fyi.browser_tests.filter

@@ -262,10 +262,6 @@
 -PlatformAppBrowserTest.PictureInPicture
 -PictureInPictureLazyBackgroundPageApiTest.PictureInPictureInBackgroundPage
 
-# Excluded from Mash because pointer events from EventGenerator aren't seen.
-# https://crbug.com/814675
--ChromeOSInfoPrivateTest.StylusSeen
-
 # Has become super flaky on linux-chromeos-rel bot. Note that the test itself
 # is also flaky on Windows and Mac even without "mash":
 # https://crbug.com/671891

testing/buildbot/filters/chromeos.single_process_mash.browser_tests.filter

@@ -85,10 +85,6 @@
 -PlatformAppBrowserTest.PictureInPicture
 -PictureInPictureLazyBackgroundPageApiTest.PictureInPictureInBackgroundPage
 
-# Excluded from Mash because pointer events from EventGenerator aren't seen.
-# https://crbug.com/814675
--ChromeOSInfoPrivateTest.StylusSeen
-
 # --------------------------------------------------
 # Tests failing only for SingleProcessMash.
 # --------------------------------------------------