Bindings templates cleanup

Style fixes
http://dev.chromium.org/developers/jinja#TOC-Style

TBR=haraken

Review URL: https://codereview.chromium.org/230063002

git-svn-id: svn://svn.chromium.org/blink/trunk@171120 bbb929c8-8fbe-4397-9dbb-9b2b20218538