Remove SkBlendImageFilter, and all tests. Its functionality has been subsumed by SkXfermodeImageFilter.

R=robertphillips@google.com

Review URL: https://codereview.chromium.org/21404002

git-svn-id: http://skia.googlecode.com/svn/trunk@10482 2bbb7eff-a529-9590-31e7-b0007b416f81
9 files changed