cros: Adds ShellPort functions for simplified display mode

ash/host/ash_window_tree_host_init_params.h

Index: ash/host/ash_window_tree_host_init_params.h
diff --git a/ash/host/ash_window_tree_host_init_params.h b/ash/host/ash_window_tree_host_init_params.h
index cf59bef35eaa95214943abad24f96073426d6b1a..4c85f9555dc4908c831f9443cb6277f6813c9a72 100644
--- a/ash/host/ash_window_tree_host_init_params.h
+++ b/ash/host/ash_window_tree_host_init_params.h
@@ -5,14 +5,20 @@
 #ifndef ASH_HOST_WINDOW_TREE_HOST_INIT_PARAMS_H_
 #define ASH_HOST_WINDOW_TREE_HOST_INIT_PARAMS_H_
 
+#include <stdint.h>
+
 #include "ash/ash_export.h"
 #include "ui/gfx/geometry/rect.h"
 
 namespace ash {
 
 struct ASH_EXPORT AshWindowTreeHostInitParams {
+  // This corresponds to display::ManagedDisplayInfo::bounds_in_native.
   gfx::Rect initial_bounds;
   bool offscreen = false;
+  int64_t display_id = 0;
+  float device_scale_factor = 0.0f;
+  float ui_scale_factor = 0.0f;
 };
 
 }  // namespace ash