Add GPU support for axis-aligned ovals:
- Add drawOval base function to SkDevice, and override in SkGpuDevice
- Move isSimilarityMatrix to SkMatrix (renamed to isSimilarity) and fixed up unit test
- Since both SkGpuDevice::drawOval() and GrContext::drawPath() can try to draw ovals, added GrContext::canDrawOval() and GrContext::internalDrawOval() to avoid duplicate code
- Hooked in axis-aligned oval fill shader
- Enabled GPU stroked circles
- Added stroked circle bench test

Review URL: https://codereview.appspot.com/7137050



git-svn-id: http://skia.googlecode.com/svn/trunk@7304 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/core/SkDrawFilter.h b/include/core/SkDrawFilter.h
index 3944257..6a50ca7 100644
--- a/include/core/SkDrawFilter.h
+++ b/include/core/SkDrawFilter.h
@@ -31,6 +31,7 @@
         kLine_Type,
         kBitmap_Type,
         kRect_Type,
+        kOval_Type,
         kPath_Type,
         kText_Type,
     };