MacViews: Ensure the RootView is in place before the first call to ReorderNativeViews

ui/views/widget/widget_unittest.cc

Index: ui/views/widget/widget_unittest.cc
diff --git a/ui/views/widget/widget_unittest.cc b/ui/views/widget/widget_unittest.cc
index 6cc7d1aaeb0aea3220af87e5b745115e25b26a82..acd8ae8f7cc7e5fde0c28052eee43463a21cbf40 100644
--- a/ui/views/widget/widget_unittest.cc
+++ b/ui/views/widget/widget_unittest.cc
@@ -3094,5 +3094,26 @@ TEST_F(WidgetTest, MouseEventTypesViaGenerator) {
   widget->CloseNow();
 }
 
+// Tests that the root view is correctly set up for Widget types that do not
+// require a non-client view, before any other views are added to the widget.
+// That is, before Widget::ReorderNativeViews() is called which, if called with
+// a root view not set, could cause the root view to get resized to the widget.
+TEST_F(WidgetTest, NonClientWindowValidAfterInit) {
+  Widget* widget = CreateTopLevelFramelessPlatformWidget();
+  View* root_view = widget->GetRootView();
+
+  // Size the root view to exceed the widget bounds.
+  const gfx::Rect test_rect(0, 0, 500, 500);
+  root_view->SetBoundsRect(test_rect);
+
+  EXPECT_NE(test_rect.size(), widget->GetWindowBoundsInScreen().size());
+
+  EXPECT_EQ(test_rect, root_view->bounds());
+  widget->ReorderNativeViews();
+  EXPECT_EQ(test_rect, root_view->bounds());
+
+  widget->CloseNow();
+}
+
 }  // namespace test
 }  // namespace views