mus: Changes SetDisplayRoot() to create actual display

services/ui/ws/window_server_delegate.h

Index: services/ui/ws/window_server_delegate.h
diff --git a/services/ui/ws/window_server_delegate.h b/services/ui/ws/window_server_delegate.h
index 337cc3880e2757f5df8055a089ad27a6239383ae..cc463b51ef00771c72ff9ad4a7bdca58cf279e62 100644
--- a/services/ui/ws/window_server_delegate.h
+++ b/services/ui/ws/window_server_delegate.h
@@ -14,6 +14,12 @@
 #include "services/ui/common/types.h"
 #include "services/ui/public/interfaces/window_tree.mojom.h"
 
+namespace display {
+
+class ScreenBase;
+
+}  // namespace

[kylechar, 2017/04/19 18:06:08]

Fix namespace close comment.

[sky, 2017/04/19 19:30:03]

This is no longer needed.

+
 namespace ui {
 
 namespace mojom {
@@ -53,6 +59,15 @@ class WindowServerDelegate {
       mojom::WindowTreeRequest* tree_request,
       mojom::WindowTreeClientPtr* client);
 
+  // Called prior to a new WindowTree being created for a
+  // WindowManagerWindowTreeFactory. |automatically_create_display_roots|
+  // mirrors that of CreateWindowTree(). See it for details.
+  virtual void OnWillCreateTreeForWindowManager(
+      bool automatically_create_display_roots);
+
+  // NOTE: only valid when |automatically_create_display_roots| is false.
+  virtual display::ScreenBase* GetScreen() = 0;
+
  protected:
   virtual ~WindowServerDelegate() {}
 };