Revert 169268 "Rename FontItalics to FontStyle to match CSS term..."

Had to revert this so we can revert 169264.

> Rename FontItalics to FontStyle to match CSS terminology
> 
> Rename the FontItalics enum, the FontDescription italics/ 
> setItalics methods and wrappers to FontStyle, style and style 
> respectively to better match the CSS terminology. 
> 
> R=dglazkov@chromium.org, adamk@chromium.org
> 
> Review URL: https://codereview.chromium.org/196983014

TBR=eae@chromium.org

Review URL: https://codereview.chromium.org/196723023

git-svn-id: svn://svn.chromium.org/blink/trunk@169272 bbb929c8-8fbe-4397-9dbb-9b2b20218538