path ops : add support for inverse fill

add inverse fill, reverse diff, and gm tests
cleaned up some interfaces
Review URL: https://codereview.chromium.org/14371011

git-svn-id: http://skia.googlecode.com/svn/trunk@8798 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp/pathops_unittest.gypi b/gyp/pathops_unittest.gypi
index ebe1d5b..21fb929 100644
--- a/gyp/pathops_unittest.gypi
+++ b/gyp/pathops_unittest.gypi
@@ -15,6 +15,7 @@
     '../tests/PathOpsDTriangleTest.cpp',
     '../tests/PathOpsDVectorTest.cpp',
     '../tests/PathOpsExtendedTest.cpp',
+    '../tests/PathOpsInverseTest.cpp',
     '../tests/PathOpsLineIntersectionTest.cpp',
     '../tests/PathOpsLineParametetersTest.cpp',
     '../tests/PathOpsOpCubicThreadedTest.cpp',