Adding int cast to prevent warning

BUG=skia:
R=fmalita@google.com, fmalita@chromium.org, bsalomon@google.com, bsalomon@chromium.org

Author: sugoi@chromium.org

Review URL: https://codereview.chromium.org/149463009

git-svn-id: http://skia.googlecode.com/svn/trunk@13285 2bbb7eff-a529-9590-31e7-b0007b416f81

samplecode/SamplePictFile.cpp

@@ -94,7 +94,7 @@ protected:
     }
 
     virtual void onDrawContent(SkCanvas* canvas) SK_OVERRIDE {
-        SkASSERT(fBBox < kBBoxTypeCount);
+        SkASSERT(static_cast<int>(fBBox) < kBBoxTypeCount);
         SkPicture** picture = fPictures + fBBox;
 
         if (!*picture) {