Gpu blend optimizations, handle more xfer modes with fractional pixel coverage

Review URL: http://codereview.appspot.com/5237062/



git-svn-id: http://skia.googlecode.com/svn/trunk@2464 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/src/GrDefaultPathRenderer.cpp b/gpu/src/GrDefaultPathRenderer.cpp
index fd56c07..14c032b 100644
--- a/gpu/src/GrDefaultPathRenderer.cpp
+++ b/gpu/src/GrDefaultPathRenderer.cpp
@@ -179,7 +179,7 @@
         return hint == kConvex_ConvexHint ||
                hint == kNonOverlappingConvexPieces_ConvexHint ||
                (hint == kSameWindingConvexPieces_ConvexHint &&
-                target.canDisableBlend() && !target.isDitherState());
+                !target.drawWillReadDst() && !target.isDitherState());
 
     }
     return false;