SkTreatAsSprite should take AA into account

src/core/SkMatrix.cpp

Index: src/core/SkMatrix.cpp
diff --git a/src/core/SkMatrix.cpp b/src/core/SkMatrix.cpp
index dfeb721d45e68394f4bf2db1906c11d708f044e3..7478114320b7ae05e4ab9b477ff17cc10660e208 100644
--- a/src/core/SkMatrix.cpp
+++ b/src/core/SkMatrix.cpp
@@ -1623,8 +1623,11 @@ void SkMatrix::toString(SkString* str) const {
 
 #include "SkMatrixUtils.h"
 
-bool SkTreatAsSprite(const SkMatrix& mat, int width, int height,
-                     unsigned subpixelBits) {
+bool SkTreatAsSprite(const SkMatrix& mat, const SkISize& size, const SkPaint& paint) {
+    static const unsigned kAntiAliasSubpixelBits = 4;

[reed1, 2016/01/07 15:29:59]

maybe a comment, like "our path aa is 2-bits, and our rect aa is 8, so we could
use 8, but in practice 4 seems enough (still looks smooth) and allows more
slightly fractional cases to fall into the fast (sprite) case."

[f(malita), 2016/01/07 15:39:35]

Done.

+
+    const unsigned subpixelBits = paint.isAntiAlias() ? kAntiAliasSubpixelBits : 0;
+
     // quick reject on affine or perspective
     if (mat.getType() & ~(SkMatrix::kScale_Mask | SkMatrix::kTranslate_Mask)) {
         return false;
@@ -1641,7 +1644,7 @@ bool SkTreatAsSprite(const SkMatrix& mat, int width, int height,
     }
 
     SkRect dst;
-    SkIRect isrc = { 0, 0, width, height };
+    SkIRect isrc = SkIRect::MakeSize(size);
 
     {
         SkRect src;