More win64 warning fixes

src/core/SkDistanceFieldGen.h

Index: src/core/SkDistanceFieldGen.h
diff --git a/src/core/SkDistanceFieldGen.h b/src/core/SkDistanceFieldGen.h
index 0510907f8c8847ec319f4c8fd037d39720542f6f..4a09ace107f16c241fdaeddbd084e5a89f952126 100644
--- a/src/core/SkDistanceFieldGen.h
+++ b/src/core/SkDistanceFieldGen.h
@@ -35,7 +35,7 @@
  */
 bool SkGenerateDistanceFieldFromA8Image(unsigned char* distanceField,
                                         const unsigned char* image,
-                                        int w, int h, int rowBytes);
+                                        int w, int h, size_t rowBytes);
 
 /** Given 1-bit mask data, generate the associated distance field
 
@@ -48,7 +48,7 @@ bool SkGenerateDistanceFieldFromA8Image(unsigned char* distanceField,
  */
 bool SkGenerateDistanceFieldFromBWImage(unsigned char* distanceField,
                                         const unsigned char* image,
-                                        int w, int h, int rowBytes);
+                                        int w, int h, size_t rowBytes);
 
 /** Given width and height of original image, return size (in bytes) of distance field
  *  @param w                 Width of the original image.