Make PopupMenuTest run on all platforms.

This is not as much of a porting effort as just straightening out the sheetmetal.

Technically, the change removes vestigal (from back at http://trac.webkit.org/changeset/14337)
shortcut of initializing Font straight out of FontPlatformData, which we don't use.

But hey, better testing as a result? Can't complain.

R=eae,ksakamoto@chromium.org
BUG=319475

Review URL: https://codereview.chromium.org/142703003

git-svn-id: svn://svn.chromium.org/blink/trunk@165415 bbb929c8-8fbe-4397-9dbb-9b2b20218538