Mask Negative Offset Repeat

Mask version of test for http://bugs.webkit.org/show_bug.cgi?id=5399 no-repeat on negatively positioned fill images is ignored.

Element with mask image starting at (-13, -13) with no-repeat set:

Element with mask image starting at (-13, -13) with repeat-y set:

Element with mask image starting at (-13, -13) with repeat-x set:

Element with mask image starting at (13, 13) with no-repeat set:

Element with mask image starting at (13, 13) with repeat-y set:

Element with mask image starting at (13, 13) with repeat-x set: