Converts ash/wm/mru_window_tracker_unittest.cc to use AshTest

services/ui/public/cpp/window.cc

Index: services/ui/public/cpp/window.cc
diff --git a/services/ui/public/cpp/window.cc b/services/ui/public/cpp/window.cc
index bc20d45694df46c8b8674b5e938223b1a56146a5..966e51888c18a26e688a91a45c1a44010347b7a9 100644
--- a/services/ui/public/cpp/window.cc
+++ b/services/ui/public/cpp/window.cc
@@ -553,6 +553,9 @@ Window::~Window() {
     DCHECK(children_.empty() || children_.front() != child);
   }
 
+  // Notify observers before clearing properties (order matches aura::Window).
+  FOR_EACH_OBSERVER(WindowObserver, observers_, OnWindowDestroyed(this));
+
   // Clear properties.
   for (auto& pair : prop_map_) {
     if (pair.second.deallocator)
@@ -560,8 +563,6 @@ Window::~Window() {
   }
   prop_map_.clear();
 
-  FOR_EACH_OBSERVER(WindowObserver, observers_, OnWindowDestroyed(this));
-
   // Invoke after observers so that can clean up any internal state observers
   // may have changed.
   if (window_tree())