WIP: Propagate SurfaceID up window tree hierarchy

services/ui/ws/platform_display_init_params.h

Index: services/ui/ws/platform_display_init_params.h
diff --git a/services/ui/ws/platform_display_init_params.h b/services/ui/ws/platform_display_init_params.h
index 99bda3f51db0584bacc779e24ffe344c7935ccea..e117a6f847dadab037f5e509904ece09b81e3dbb 100644
--- a/services/ui/ws/platform_display_init_params.h
+++ b/services/ui/ws/platform_display_init_params.h
@@ -16,8 +16,9 @@ class Connector;
 
 namespace ui {
 
-class GpuState;
-class SurfacesState;
+namespace surfaces {
+class DisplayCompositor;
+}
 
 namespace ws {
 
@@ -26,7 +27,7 @@ struct PlatformDisplayInitParams {
   PlatformDisplayInitParams(const PlatformDisplayInitParams& other);
   ~PlatformDisplayInitParams();
 
-  scoped_refptr<SurfacesState> surfaces_state;
+  scoped_refptr<surfaces::DisplayCompositor> display_compositor;
 
   gfx::Rect display_bounds;
   int64_t display_id;