6722802: Code improvement and warnings removing from the javax.swing.text package
Summary: Removed unnecessary castings and other warnings
Reviewed-by: peterz
Contributed-by: Florian Brunner <fbrunnerlist@gmx.ch>
cfeea66a3fa8ca3686a7cfa2d0ce8ab0169f168d jdk7-b24
cbc8ad9dd0e085a607427ea35411990982f19a36 jdk7-b25