Fix event dispatching offset problem in the client-lib in high-dpi mode. (transform)

ui/aura/mus/window_tree_client.cc

Index: ui/aura/mus/window_tree_client.cc
diff --git a/ui/aura/mus/window_tree_client.cc b/ui/aura/mus/window_tree_client.cc
index b71391bc5bab8f5977235c55f7e570fe3f791b1c..b7f687be130855706b62fa0bc651c0c837cea73b 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -1153,8 +1153,13 @@ void WindowTreeClient::OnWindowInputEvent(uint32_t event_id,
   // to WindowTreeHost we need it to be relative to WindowTreeHost.
   if (event->IsLocatedEvent()) {
     gfx::Point host_location = event->AsLocatedEvent()->location();
-    aura::Window::ConvertPointToTarget(window->GetWindow(), host->window(),
-                                       &host_location);
+    gfx::Transform transform;
+    window->GetWindow()->layer()->GetTargetTransformRelativeTo(
+        host->window()->layer(), &transform);
+    transform.Scale(1, ScaleFactorForDisplay(window->GetWindow()));
+    auto transformed_host_location = gfx::Point3F(gfx::PointF(host_location));
+    transform.TransformPoint(&transformed_host_location);
+    host_location = gfx::ToFlooredPoint(transformed_host_location.AsPointF());
     event->AsLocatedEvent()->set_location(host_location);
   }