Implement large cursors in Mushrome.

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 b69d69d4946900ce46897ad5dd44e1af744499e9..fb078bcb8149c24182f1519343404d219f9c3172 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -1884,6 +1884,11 @@ void WindowTreeClient::SetCursorVisible(bool visible) {
     window_manager_client_->WmSetCursorVisible(visible);
 }
 
+void WindowTreeClient::SetCursorSize(ui::CursorSize cursor_size) {
+  if (window_manager_client_)
+    window_manager_client_->WmSetCursorSize(cursor_size);
+}
+
 void WindowTreeClient::SetGlobalOverrideCursor(
     base::Optional<ui::CursorData> cursor) {
   if (window_manager_client_)