[Effen] Expose various private members so that fn classes can exist outside fn.dart This is needed to create a ScaffoldContainer in scaffold.dart.
[Effen] Expose various private members so that fn classes can exist outside fn.dart
This is needed to create a ScaffoldContainer in scaffold.dart.

This exposes:
  UINode._root => root
  UINode._removeChild => removeChild
  RenderNodeWrapper._createNode => createNode
  RenderNodeWrapper._emptyNode => emptyNode
  RenderNodeWrapper._syncRenderNode => syncRenderNode

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/1148323004

jason-simmons/sky_engine,xunmengfeng/engine,jimsimon/sky_engine,rmacnak-google/engine,jamesr/sky_engine,mpcomplete/engine,qiankunshe/sky_engine,tvolkert/engine,devoncarew/sky_engine,afandria/sky_engine,chinmaygarde/flutter_engine,jamesr/flutter_engine,xunmengfeng/engine,TribeMedia/sky_engine,mpcomplete/engine,jimsimon/sky_engine,aam/engine,krisgiesing/sky_engine,mpcomplete/engine,chinmaygarde/flutter_engine,cdotstout/sky_engine,TribeMedia/sky_engine,mpcomplete/flutter_engine,lyceel/engine,qiankunshe/sky_engine,tvolkert/engine,TribeMedia/sky_engine,lyceel/engine,jimsimon/sky_engine,mikejurka/engine,zhangxq5012/sky_engine,axinging/sky_engine,jamesr/flutter_engine,aam/engine,iansf/sky_engine,devoncarew/sky_engine,cdotstout/sky_engine,tvolkert/engine,axinging/sky_engine,Hixie/sky_engine,jamesr/flutter_engine,devoncarew/engine,iansf/sky_engine,zhangxq5012/sky_engine,chinmaygarde/sky_engine,jamesr/sky_engine,mpcomplete/engine,takaaptech/sky_engine,axinging/sky_engine,flutter/engine,jason-simmons/flutter_engine,jamesr/flutter_engine,aam/engine,krisgiesing/sky_engine,mpcomplete/flutter_engine,qiankunshe/sky_engine,tvolkert/engine,mxia/engine,abarth/sky_engine,devoncarew/engine,mxia/engine,jimsimon/sky_engine,abarth/sky_engine,mxia/engine,abarth/sky_engine,mpcomplete/engine,chinmaygarde/sky_engine,devoncarew/engine,lyceel/engine,rmacnak-google/engine,lyceel/engine,iansf/sky_engine,flutter/engine,TribeMedia/sky_engine,mpcomplete/flutter_engine,jamesr/sky_engine,lyceel/engine,chinmaygarde/flutter_engine,chinmaygarde/sky_engine,jamesr/flutter_engine,chinmaygarde/sky_engine,mdakin/engine,cdotstout/sky_engine,mdakin/engine,afandria/sky_engine,Hixie/sky_engine,afandria/sky_engine,zhangxq5012/sky_engine,iansf/sky_engine,jamesr/flutter_engine,rmacnak-google/engine,jamesr/sky_engine,chinmaygarde/flutter_engine,jamesr/sky_engine,chinmaygarde/sky_engine,mxia/engine,mxia/engine,chinmaygarde/flutter_engine,TribeMedia/sky_engine,cdotstout/sky_engine,rmacnak-google/engine,zhangxq5012/sky_engine,mpcomplete/flutter_engine,mdakin/engine,qiankunshe/sky_engine,mxia/engine,axinging/sky_engine,abarth/sky_engine,iansf/sky_engine,qiankunshe/sky_engine,krisgiesing/sky_engine,xunmengfeng/engine,jamesr/sky_engine,zhangxq5012/sky_engine,mpcomplete/engine,axinging/sky_engine,xunmengfeng/engine,jamesr/flutter_engine,aam/engine,jason-simmons/flutter_engine,zhangxq5012/sky_engine,devoncarew/engine,jamesr/sky_engine,mikejurka/engine,krisgiesing/sky_engine,jamesr/flutter_engine,mikejurka/engine,lyceel/engine,afandria/sky_engine,takaaptech/sky_engine,takaaptech/sky_engine,afandria/sky_engine,tvolkert/engine,afandria/sky_engine,jason-simmons/sky_engine,devoncarew/sky_engine,qiankunshe/sky_engine,mpcomplete/flutter_engine,jason-simmons/flutter_engine,chinmaygarde/sky_engine,cdotstout/sky_engine,mxia/engine,tvolkert/engine,TribeMedia/sky_engine,takaaptech/sky_engine,flutter/engine,devoncarew/engine,flutter/engine,devoncarew/sky_engine,iansf/sky_engine,cdotstout/sky_engine,takaaptech/sky_engine,takaaptech/sky_engine,mikejurka/engine,mdakin/engine,xunmengfeng/engine,iansf/sky_engine,devoncarew/sky_engine,zhangxq5012/sky_engine,TribeMedia/sky_engine,jimsimon/sky_engine,jimsimon/sky_engine,Hixie/sky_engine,jason-simmons/sky_engine,mxia/engine,Hixie/sky_engine,devoncarew/sky_engine,Hixie/sky_engine,mdakin/engine,TribeMedia/sky_engine,jamesr/flutter_engine,mpcomplete/engine,mikejurka/engine,aam/engine,aam/engine,mikejurka/engine,Hixie/sky_engine,iansf/sky_engine,xunmengfeng/engine,jason-simmons/flutter_engine,jason-simmons/sky_engine,rmacnak-google/engine,abarth/sky_engine,flutter/engine,axinging/sky_engine,zhangxq5012/sky_engine,chinmaygarde/flutter_engine,jason-simmons/flutter_engine,krisgiesing/sky_engine,takaaptech/sky_engine,flutter/engine,devoncarew/sky_engine,jimsimon/sky_engine,rmacnak-google/engine,qiankunshe/sky_engine,devoncarew/engine,jimsimon/sky_engine,jason-simmons/sky_engine,Hixie/sky_engine,aam/engine,xunmengfeng/engine,cdotstout/sky_engine,krisgiesing/sky_engine,mdakin/engine,axinging/sky_engine,krisgiesing/sky_engine,jimsimon/sky_engine,jason-simmons/flutter_engine,takaaptech/sky_engine,afandria/sky_engine,Hixie/sky_engine,jason-simmons/sky_engine,axinging/sky_engine,chinmaygarde/flutter_engine,jason-simmons/flutter_engine,takaaptech/sky_engine,mpcomplete/flutter_engine,devoncarew/engine,mikejurka/engine,lyceel/engine,jason-simmons/sky_engine,afandria/sky_engine,mdakin/engine,abarth/sky_engine,aam/engine,mikejurka/engine,mikejurka/engine,jason-simmons/flutter_engine,rmacnak-google/engine,flutter/engine,zhangxq5012/sky_engine,mdakin/engine,flutter/engine,TribeMedia/sky_engine,qiankunshe/sky_engine,axinging/sky_engine,abarth/sky_engine,mpcomplete/engine,tvolkert/engine,chinmaygarde/sky_engine