Fixing the drawing of blurred shodows for hairline paths with software rendering

BUG=http://code.google.com/p/chromium/issues/detail?id=121251
REVIEW=http://codereview.appspot.com/5981053/



git-svn-id: http://skia.googlecode.com/svn/trunk@3592 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/effects/SkLayerRasterizer.cpp b/src/effects/SkLayerRasterizer.cpp
index 81263d1..8899b42 100644
--- a/src/effects/SkLayerRasterizer.cpp
+++ b/src/effects/SkLayerRasterizer.cpp
@@ -74,7 +74,8 @@
         SkMask  mask;
         if (!SkDraw::DrawToMask(devPath, clipBounds, paint.getMaskFilter(),
                                 &matrix, &mask,
-                                SkMask::kJustComputeBounds_CreateMode)) {
+                                SkMask::kJustComputeBounds_CreateMode,
+                                SkPaint::kFill_Style)) {
             return false;
         }