Makes ash/mus use RootWindowControllerCommon

ash/mus/property_util.cc

Index: ash/mus/property_util.cc
diff --git a/ash/mus/property_util.cc b/ash/mus/property_util.cc
index 9d1922ea9a65b1d86192092ed192ab56a4518482..3daf0de42c5bea90ac2b409bcaf8f18e8c70ebcb 100644
--- a/ash/mus/property_util.cc
+++ b/ash/mus/property_util.cc
@@ -74,12 +74,14 @@ gfx::Size GetWindowPreferredSize(const ::mus::Window* window) {
   return gfx::Size();
 }
 
-mojom::Container GetRequestedContainer(const ::mus::Window* window) {
-  if (window->HasSharedProperty(mojom::kWindowContainer_Property)) {
-    return static_cast<mojom::Container>(
-        window->GetSharedProperty<int32_t>(mojom::kWindowContainer_Property));
-  }
-  return mojom::Container::USER_PRIVATE_WINDOWS;
+bool GetRequestedContainer(const ::mus::Window* window,
+                           mojom::Container* container) {
+  if (!window->HasSharedProperty(mojom::kWindowContainer_Property))
+    return false;
+
+  *container = static_cast<mojom::Container>(
+      window->GetSharedProperty<int32_t>(mojom::kWindowContainer_Property));
+  return true;
 }
 
 int32_t GetResizeBehavior(const ::mus::Window* window) {