This new changelist also introduces a new image filter called SkRectShaderImageFilter which is make to simply apply a shader on a region without using any inputs.
TEST=Added ShaderImageFilter test
Review URL: https://codereview.appspot.com/7300046
git-svn-id: http://skia.googlecode.com/svn/trunk@7808 2bbb7eff-a529-9590-31e7-b0007b416f81