[WIP] Make content_shell run under Wayland

ui/ozone/public/ozone_platform.h

Index: ui/ozone/public/ozone_platform.h
diff --git a/ui/ozone/public/ozone_platform.h b/ui/ozone/public/ozone_platform.h
index f530af37d9d9a063fca34fde83a01eda59d68b52..a15e335baf2f7093bc378aa5dd007dbdaccd6f93 100644
--- a/ui/ozone/public/ozone_platform.h
+++ b/ui/ozone/public/ozone_platform.h
@@ -30,6 +30,7 @@ class InputController;
 class GpuPlatformSupportHost;
 class NativeDisplayDelegate;
 class OverlayManagerOzone;
+class OzonePlatformScreenDelegate;
 class PlatformWindow;
 class PlatformWindowDelegate;
 class SurfaceFactoryOzone;
@@ -114,6 +115,7 @@ class OZONE_EXPORT OzonePlatform {
   // A default do-nothing implementation is provided to permit platform
   // implementations to opt out of implementing any Mojo interfaces.
   virtual void AddInterfaces(shell::InterfaceRegistry* registry);
+  virtual void SetScreenOutputObserver(OzonePlatformScreenDelegate*) {}
 
  private:
   virtual void InitializeUI() = 0;