[mus+ash] Fixes minimum browser window size (store / retrieve kPreferredSize property)

ash/public/cpp/mus_property_mirror_ash.cc

Index: ash/public/cpp/mus_property_mirror_ash.cc
diff --git a/ash/public/cpp/mus_property_mirror_ash.cc b/ash/public/cpp/mus_property_mirror_ash.cc
index a9b634eeffbf3aa47c7eb46dbabc97adf9d840e9..66579aa72400a15e9c2a28109df01d033cba1bb8 100644
--- a/ash/public/cpp/mus_property_mirror_ash.cc
+++ b/ash/public/cpp/mus_property_mirror_ash.cc
@@ -47,6 +47,8 @@ void MusPropertyMirrorAsh::MirrorPropertyFromWidgetWindowToRootWindow(
   } else if (key == aura::client::kDrawAttentionKey) {
     bool value = window->GetProperty(aura::client::kDrawAttentionKey);
     root_window->SetProperty(aura::client::kDrawAttentionKey, value);
+  } else if (key == aura::client::kMinimumSize) {
+    MirrorOwnedProperty(window, root_window, aura::client::kMinimumSize);
   } else if (key == aura::client::kTitleKey) {
     MirrorOwnedProperty(window, root_window, aura::client::kTitleKey);
   } else if (key == aura::client::kWindowIconKey) {