Fix even more warnings.

After this, only 2 generated files are left on mac, almost ready to turn
on -Wall.

BUG=312287
R=dglazkov@chromium.org

Review URL: https://codereview.chromium.org/48273004

git-svn-id: svn://svn.chromium.org/blink/trunk@160760 bbb929c8-8fbe-4397-9dbb-9b2b20218538