Pass root ServerWindow id to FrameGenerator.

services/ui/ws/platform_display_init_params.cc

Index: services/ui/ws/platform_display_init_params.cc
diff --git a/services/ui/ws/platform_display_init_params.cc b/services/ui/ws/platform_display_init_params.cc
index 4396754764bdabafbdfa84f1b3980060c455f33c..213483866944750377d5f8b4f97fd7e713400006 100644
--- a/services/ui/ws/platform_display_init_params.cc
+++ b/services/ui/ws/platform_display_init_params.cc
@@ -5,6 +5,7 @@
 #include "services/ui/ws/platform_display_init_params.h"
 
 #include "services/ui/surfaces/display_compositor.h"
+#include "services/ui/ws/server_window.h"
 #include "ui/display/display.h"
 
 namespace ui {
@@ -13,6 +14,9 @@ namespace ws {
 PlatformDisplayInitParams::PlatformDisplayInitParams()
     : display_id(display::Display::kInvalidDisplayID) {}
 
+PlatformDisplayInitParams::PlatformDisplayInitParams(
+    const PlatformDisplayInitParams& other) = default;
+
 PlatformDisplayInitParams::~PlatformDisplayInitParams() {}
 
 }  // namespace ws