Refactor and push window properties up to class properties.

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 9a4c1065d49ec4a0d9b071a135317d39d20ddd43..f925d8000284f8f85a5f7c5baec0b178e9b4eb35 100644
--- a/ui/aura/mus/window_tree_client.cc
+++ b/ui/aura/mus/window_tree_client.cc
@@ -65,7 +65,7 @@ inline uint16_t HiWord(uint32_t id) {
   return static_cast<uint16_t>((id >> 16) & 0xFFFF);
 }
 
-struct WindowPortPropertyDataMus : public WindowPortPropertyData {
+struct WindowPortPropertyDataMus : public ui::PropertyData {
   std::string transport_name;
   std::unique_ptr<std::vector<uint8_t>> transport_value;
 };
@@ -701,7 +701,7 @@ void WindowTreeClient::OnWindowMusSetVisible(WindowMus* window, bool visible) {
   tree_->SetWindowVisibility(change_id, window->server_id(), visible);
 }
 
-std::unique_ptr<WindowPortPropertyData>
+std::unique_ptr<ui::PropertyData>
 WindowTreeClient::OnWindowMusWillChangeProperty(WindowMus* window,
                                                 const void* key) {
   if (IsInternalProperty(key))
@@ -720,7 +720,7 @@ WindowTreeClient::OnWindowMusWillChangeProperty(WindowMus* window,
 void WindowTreeClient::OnWindowMusPropertyChanged(
     WindowMus* window,
     const void* key,
-    std::unique_ptr<WindowPortPropertyData> data) {
+    std::unique_ptr<ui::PropertyData> data) {
   if (HandleInternalPropertyChanged(window, key) || !data)
     return;