Make PestoDemoState.scaffoldKey non-static so Favorites can instantiate a second PestoDemo (#5005)
Make PestoDemoState.scaffoldKey non-static so Favorites can instantiate a second PestoDemo (#5005)

Fixes https://github.com/flutter/flutter/issues/4996
cbracken/flutter,tvolkert/flutter,Hixie/flutter,tvolkert/flutter,Hixie/flutter,tvolkert/flutter,flutter/flutter,cbracken/flutter,Hixie/flutter,tvolkert/flutter,turnidge/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,Hixie/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,flutter/flutter,cbracken/flutter,Hixie/flutter,cbracken/flutter,cbracken/flutter,Hixie/flutter,flutter/flutter,tvolkert/flutter,cbracken/flutter,flutter/flutter,turnidge/flutter,turnidge/flutter,Hixie/flutter,Hixie/flutter,turnidge/flutter,tvolkert/flutter,Hixie/flutter,turnidge/flutter,Hixie/flutter,cbracken/flutter,flutter/flutter,cbracken/flutter,cbracken/flutter,tvolkert/flutter,cbracken/flutter