Add PlatformScreenDelegate and start implementation.

services/ui/display/platform_screen_impl_ozone.h

Index: services/ui/display/platform_screen_impl_ozone.h
diff --git a/services/ui/display/platform_screen_impl_ozone.h b/services/ui/display/platform_screen_impl_ozone.h
index 0e89b57a09fbb93802d1d9382c08640e243431e7..d7282df3bcce91440d9d324d84057ffe994bd51d 100644
--- a/services/ui/display/platform_screen_impl_ozone.h
+++ b/services/ui/display/platform_screen_impl_ozone.h
@@ -28,10 +28,7 @@ class PlatformScreenImplOzone : public PlatformScreen,
 
  private:
   // PlatformScreen:
-  void Init() override;  // Must not be called until after the ozone platform is
-                         // initialized.
-  void ConfigurePhysicalDisplay(
-      const ConfiguredDisplayCallback& callback) override;
+  void Init(PlatformScreenDelegate* delegate) override;
   int64_t GetPrimaryDisplayId() const override;
 
   // ui::DisplayConfigurator::Observer:
@@ -41,6 +38,7 @@ class PlatformScreenImplOzone : public PlatformScreen,
       const ui::DisplayConfigurator::DisplayStateList& displays,
       ui::MultipleDisplayState failed_new_state) override;
 
+  PlatformScreenDelegate* delegate_ = nullptr;
   ui::DisplayConfigurator display_configurator_;
 
   // TODO(kylechar): These values can/should be replaced by DisplayLayout.
@@ -48,9 +46,6 @@ class PlatformScreenImplOzone : public PlatformScreen,
   std::set<uint64_t> displays_;
   gfx::Point next_display_origin_;
 
-  // Callback for when new displays are configured.
-  ConfiguredDisplayCallback callback_;
-
   DISALLOW_COPY_AND_ASSIGN(PlatformScreenImplOzone);
 };