Add FakeDisplayDelegate for off device usage.

ui/ozone/common/native_display_delegate_ozone.h

Index: ui/ozone/common/native_display_delegate_ozone.h
diff --git a/ui/ozone/common/native_display_delegate_ozone.h b/ui/ozone/common/native_display_delegate_ozone.h
index e70c193d43585c40f6d40044c336f0ab18b5b93d..9127fd22bf0ef0563d0eb510fd7032a5fddf29e6 100644
--- a/ui/ozone/common/native_display_delegate_ozone.h
+++ b/ui/ozone/common/native_display_delegate_ozone.h
@@ -55,11 +55,7 @@ class NativeDisplayDelegateOzone : public NativeDisplayDelegate {
                           const std::vector<float>& correction_matrix) override;
   void AddObserver(NativeDisplayObserver* observer) override;
   void RemoveObserver(NativeDisplayObserver* observer) override;
-
- protected:
-  std::vector<std::unique_ptr<DisplaySnapshot>>& displays() {
-    return displays_;
-  }
+  display::FakeDisplayController* GetFakeDisplayController() override;
 
  private:
   std::vector<std::unique_ptr<DisplaySnapshot>> displays_;