Add prescale option to deferred params

include/core/SkImage.h

Index: include/core/SkImage.h
diff --git a/include/core/SkImage.h b/include/core/SkImage.h
index 50a9f5761267c200442233063d5136257f28c94c..e9aedc9366436571fd58d1562a1315ffe009e24d 100644
--- a/include/core/SkImage.h
+++ b/include/core/SkImage.h
@@ -343,8 +343,13 @@ public:
 
     /** Drawing params for which a deferred texture image data should be optimized. */
     struct DeferredTextureImageUsageParams {
+        DeferredTextureImageUsageParams() : fPreScaleMipLevel(0) {}
+        DeferredTextureImageUsageParams(const SkMatrix matrix, const SkFilterQuality quality, 
+                                        int preScaleMipLevel)
+            : fMatrix(matrix), fQuality(quality), fPreScaleMipLevel(preScaleMipLevel) {}
         SkMatrix        fMatrix;
         SkFilterQuality fQuality;
+        int             fPreScaleMipLevel;
     };
 
     /**