Fix bug where text input would remain underlined upon losing focused. (#5027)
Fix bug where text input would remain underlined upon losing focused. (#5027)

BUG=https://github.com/flutter/flutter/issues/4904
Hixie/flutter,cbracken/flutter,turnidge/flutter,flutter/flutter,cbracken/flutter,flutter/flutter,cbracken/flutter,Hixie/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,flutter/flutter,tvolkert/flutter,Hixie/flutter,Hixie/flutter,cbracken/flutter,flutter/flutter,Hixie/flutter,Hixie/flutter,cbracken/flutter,cbracken/flutter,tvolkert/flutter,turnidge/flutter,Hixie/flutter,tvolkert/flutter,cbracken/flutter,cbracken/flutter,tvolkert/flutter,tvolkert/flutter,turnidge/flutter,cbracken/flutter,cbracken/flutter,tvolkert/flutter,turnidge/flutter,tvolkert/flutter,flutter/flutter,flutter/flutter,flutter/flutter,Hixie/flutter,flutter/flutter,flutter/flutter,Hixie/flutter,tvolkert/flutter,Hixie/flutter,turnidge/flutter