Makes WindowTreeHostMus supply properties directly to window creation

ui/aura/mus/window_tree_host_mus.h

Index: ui/aura/mus/window_tree_host_mus.h
diff --git a/ui/aura/mus/window_tree_host_mus.h b/ui/aura/mus/window_tree_host_mus.h
index 40473cf39dc9ed839fa74ab6e91884b0a7b5f4ff..e883a0f5ef2c6f113da204302ce4e60d9a69741f 100644
--- a/ui/aura/mus/window_tree_host_mus.h
+++ b/ui/aura/mus/window_tree_host_mus.h
@@ -30,11 +30,18 @@ class WindowTreeHostMusDelegate;
 
 class AURA_EXPORT WindowTreeHostMus : public aura::WindowTreeHostPlatform {
  public:
+  // |properties| are applied to the window created by this class (using
+  // PropertyConverter).
   WindowTreeHostMus(
       std::unique_ptr<WindowPortMus> window_port,
       WindowTreeClient* window_tree_client,
       int64_t display_id,
       const std::map<std::string, std::vector<uint8_t>>* properties = nullptr);
+
+  // This constructor is intended for creating top level windows in
+  // non-window-manager code. |properties| are properties passed verbatim to
+  // the server, e.g. no conversion is done, and then applied to the window

[msw, 2016/12/02 00:31:08]

Isn't it possible that some of these *are* converted to aura::WindowProperty
values if the key is registered and we create a corresponding aura::Window?

[sky, 2016/12/02 01:08:43]

Ya, sorry, maybe my comment isn't clear. Is the new one any better?

+  // created by this class (using PropertyConverter).
   explicit WindowTreeHostMus(
       WindowTreeClient* window_tree_client,
       const std::map<std::string, std::vector<uint8_t>>* properties = nullptr);