Fix warning after bbe43a9ce0.

TBR=robertphillips@google.com

Review URL: https://codereview.chromium.org/108973006

git-svn-id: http://skia.googlecode.com/svn/trunk@12614 2bbb7eff-a529-9590-31e7-b0007b416f81

samplecode/SamplePictFile.cpp

@@ -99,7 +99,7 @@ private:
 
         kLast_BBoxType = kTileGrid_BBoxType
     };
-    static const unsigned kBBoxTypeCount = kLast_BBoxType + 1;
+    static const int kBBoxTypeCount = kLast_BBoxType + 1;
 
     SkString    fFilename;
     SkPicture*  fPictures[kBBoxTypeCount];