[mus+ash] Implements hit-test client in Aura

ui/aura/BUILD.gn

Index: ui/aura/BUILD.gn
diff --git a/ui/aura/BUILD.gn b/ui/aura/BUILD.gn
index fad479435f1c3d0dfe3fadd3dab9e1893663f899..bf40cb82821019585685610700df6b3e451f92bf 100644
--- a/ui/aura/BUILD.gn
+++ b/ui/aura/BUILD.gn
@@ -43,6 +43,7 @@ component("aura") {
     "mus/focus_synchronizer.h",
     "mus/focus_synchronizer_delegate.h",
     "mus/focus_synchronizer_observer.h",
+    "mus/hit_test_data_provider_mus.h",
     "mus/in_flight_change.h",
     "mus/input_method_mus.h",
     "mus/mus_context_factory.h",
@@ -105,6 +106,7 @@ component("aura") {
     "mus/client_surface_embedder.cc",
     "mus/drag_drop_controller_mus.cc",
     "mus/focus_synchronizer.cc",
+    "mus/hit_test_data_provider_mus.cc",
     "mus/in_flight_change.cc",
     "mus/input_method_mus.cc",
     "mus/mus_context_factory.cc",
@@ -333,6 +335,7 @@ executable("demo") {
 test("aura_unittests") {
   sources = [
     "gestures/gesture_recognizer_unittest.cc",
+    "mus/hit_test_data_provider_mus_unittest.cc",
     "mus/input_method_mus_unittest.cc",
     "mus/os_exchange_data_provider_mus_unittest.cc",
     "mus/property_converter_unittest.cc",