Re-enable hotseat browser test

Re-enable HotseatShelfAppBrowserTest.TappingAppIconsHidesHotseat. Fix
one things: In ShelfWidget, contextual nudge related function should
not be called when the contextual nudge feature is disabled.

Verify this CL with MSAN test.

Bug: 1021011
Change-Id: Iff1755001e41e28cfe0490e014502ad711e0b90c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2207613
Commit-Queue: Andrew Xu <andrewxu@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#772081}

ash/shelf/shelf_widget.cc

@@ -1006,7 +1006,8 @@ void ShelfWidget::OnGestureEvent(ui::GestureEvent* event) {
 
   // Tap on in-app shelf should show a contextual nudge for in-app to home
   // gesture.
-  if (event->type() == ui::ET_GESTURE_TAP && ShelfConfig::Get()->is_in_app()) {
+  if (event->type() == ui::ET_GESTURE_TAP && ShelfConfig::Get()->is_in_app() &&
+      features::AreContextualNudgesEnabled()) {
     if (delegate_view_->drag_handle()->MaybeShowDragHandleNudge()) {
       event->StopPropagation();
       return;

chrome/browser/ui/ash/launcher/chrome_launcher_controller_browsertest.cc

@@ -2431,17 +2431,10 @@ IN_PROC_BROWSER_TEST_F(HotseatShelfAppBrowserTest, LaunchAppFromContextMenu) {
             controller->shelf()->shelf_layout_manager()->hotseat_state());
 }
 
-// crbug.com/1021011: Disable on ChromeOS
-#if defined(OS_CHROMEOS)
-#define MAYBE_TappingAppIconsHidesHotseat DISABLED_TappingAppIconsHidesHotseat
-#else
-#define MAYBE_TappingAppIconsHidesHotseat TappingAppIconsHidesHotseat
-#endif
-
 // Tests that launching and switching apps by tapping shelf buttons hides the
 // hotseat.
 IN_PROC_BROWSER_TEST_F(HotseatShelfAppBrowserTest,
-                       MAYBE_TappingAppIconsHidesHotseat) {
+                       TappingAppIconsHidesHotseat) {
   ash::Shell::Get()->tablet_mode_controller()->SetEnabledForTest(true);
 
   // Create two apps, then extend the hotseat.