promote SkImage::AlphaType to SkAlphaType

include/core/SkSurface.h

Index: include/core/SkSurface.h
diff --git a/include/core/SkSurface.h b/include/core/SkSurface.h
index 663cea08755758d4a9dd2f8e7d5100749084b7b7..d197a57eaf3b89e928bc4d3bffce92524072757a 100644
--- a/include/core/SkSurface.h
+++ b/include/core/SkSurface.h
@@ -53,7 +53,7 @@ public:
      */
     static SkSurface* NewRasterPMColor(int width, int height) {
         SkImage::Info info = {
-            width, height, SkImage::kPMColor_ColorType, SkImage::kPremul_AlphaType
+            width, height, SkImage::kPMColor_ColorType, kPremul_SkAlphaType
         };
         return NewRaster(info);
     }