views/mus: Add a test to verify that Widget receives events correctly.

ui/views/mus/native_widget_mus_unittest.cc

Index: ui/views/mus/native_widget_mus_unittest.cc
diff --git a/ui/views/mus/native_widget_mus_unittest.cc b/ui/views/mus/native_widget_mus_unittest.cc
index 88acd98465eddad7526bff0f541a51b12e8c9bbf..e4b7fb34c633c1c40af04fa12c92f1e3325118c2 100644
--- a/ui/views/mus/native_widget_mus_unittest.cc
+++ b/ui/views/mus/native_widget_mus_unittest.cc
@@ -7,6 +7,7 @@
 #include "base/callback.h"
 #include "base/macros.h"
 #include "components/mus/public/cpp/property_type_converters.h"
+#include "components/mus/public/cpp/tests/window_tree_client_impl_private.h"
 #include "components/mus/public/cpp/window.h"
 #include "components/mus/public/cpp/window_property.h"
 #include "components/mus/public/cpp/window_tree_connection.h"
@@ -17,6 +18,7 @@
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/aura/window.h"
 #include "ui/events/event.h"
+#include "ui/events/test/test_event_handler.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/image/image_skia.h"
 #include "ui/gfx/skia_util.h"
@@ -363,6 +365,25 @@ TEST_F(NativeWidgetMusTest, FocusChildAuraWindow) {
   EXPECT_EQ(widget.GetNativeView(), active_window);
 }
 
+TEST_F(NativeWidgetMusTest, WidgetReceivesEvent) {
+  std::unique_ptr<Widget> widget(CreateWidget(nullptr));
+  widget->Show();
+
+  View* content = new HandleMousePressView;
+  content->SetBounds(10, 20, 90, 180);
+  widget->GetContentsView()->AddChildView(content);
+
+  ui::test::TestEventHandler handler;
+  content->AddPreTargetHandler(&handler);
+
+  std::unique_ptr<ui::MouseEvent> mouse = CreateMouseEvent();
+  NativeWidgetMus* native_widget =
+      static_cast<NativeWidgetMus*>(widget->native_widget_private());
+  mus::WindowTreeClientImplPrivate test_api(native_widget->window());
+  test_api.CallOnWindowInputEvent(native_widget->window(), *mouse);
+  EXPECT_EQ(1, handler.num_mouse_events());
+}
+
 // Tests that an incoming UI event is acked with the handled status.
 TEST_F(NativeWidgetMusTest, EventAcked) {
   std::unique_ptr<Widget> widget(CreateWidget(nullptr));