Scale client area, hit test mask and bounds by device_scale_factor.

services/ui/public/cpp/tests/BUILD.gn

Index: services/ui/public/cpp/tests/BUILD.gn
diff --git a/services/ui/public/cpp/tests/BUILD.gn b/services/ui/public/cpp/tests/BUILD.gn
index c86fa8e2e64744239afde353cdb70b23f7202ff8..6bc6e6bef6b9ff2bcaddf55c6bd269362ce523e3 100644
--- a/services/ui/public/cpp/tests/BUILD.gn
+++ b/services/ui/public/cpp/tests/BUILD.gn
@@ -47,6 +47,7 @@ static_library("test_support") {
     "//services/ui/common:mus_common",
     "//services/ui/public/cpp",
     "//testing/gtest",
+    "//ui/display:test_support",
     "//ui/gl",
   ]
 }
@@ -73,6 +74,7 @@ test("mus_public_unittests") {
     "//services/ui/public/cpp",
     "//services/ui/public/cpp:internal_or_test",
     "//testing/gtest",
+    "//ui/display:test_support",
     "//ui/events",
     "//ui/gfx:test_support",
     "//ui/gfx/geometry",