Webfont fetch should be CORS-enabled even for same-origin URL

      Before this patch, webfont request was made with no-cors mode when the
URL of font face was same-origin. However, that same-origin request may
be redirected to another origin.

This patch makes webfont requests use cors mode for (initially)
same-origin requests too, in order to let ResourceFetcher handle
same/cross origin stuff. (This matches how <img crossorigin> works.)

BUG=512678
TEST=http/tests/webfont/webfont-cors.html

Review URL: https://codereview.chromium.org/1250793008

git-svn-id: svn://svn.chromium.org/blink/trunk@199364 bbb929c8-8fbe-4397-9dbb-9b2b20218538