Wires up WindowTreeClient::SetDisplayRoot()

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 b84efb4de91348693ebee5fa1641fd4bae9d2c97..ee7eba1ea0b69aad458e827c63b3bfcdc626f8e6 100644
--- a/ui/aura/mus/window_tree_host_mus.h
+++ b/ui/aura/mus/window_tree_host_mus.h
@@ -26,6 +26,7 @@ class InputMethodMus;
 class WindowTreeClient;
 class WindowTreeHostMusDelegate;
 
+struct DisplayInitParams;
 struct WindowTreeHostMusInitParams;
 
 class AURA_EXPORT WindowTreeHostMus : public aura::WindowTreeHostPlatform {
@@ -79,6 +80,10 @@ class AURA_EXPORT WindowTreeHostMus : public aura::WindowTreeHostPlatform {
   // PerformWindowMove().
   void CancelWindowMove();
 
+  // Used during initial setup. Returns the DisplayInitParams
+  // supplied to the constructor.
+  std::unique_ptr<DisplayInitParams> ReleaseDisplayInitParams();
+
   // Intended only for WindowTreeClient to call.
   void set_display_id(int64_t id) { display_id_ = id; }
   int64_t display_id() const { return display_id_; }
@@ -104,6 +109,8 @@ class AURA_EXPORT WindowTreeHostMus : public aura::WindowTreeHostPlatform {
 
   std::unique_ptr<InputMethodMus> input_method_;
 
+  std::unique_ptr<DisplayInitParams> display_init_params_;
+
   DISALLOW_COPY_AND_ASSIGN(WindowTreeHostMus);
 };