Second wave of Win64 warning cleanup

https://codereview.chromium.org/27343002/



git-svn-id: http://skia.googlecode.com/svn/trunk@11778 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/GrAtlas.h b/src/gpu/GrAtlas.h
index d3deba5..3d68698 100644
--- a/src/gpu/GrAtlas.h
+++ b/src/gpu/GrAtlas.h
@@ -54,7 +54,7 @@
     GrRectanizer*           fRects;
     GrAtlasMgr*             fAtlasMgr;
     GrIPoint16              fOffset;
-    int                     fBytesPerPixel;
+    size_t                  fBytesPerPixel;
 
     friend class GrAtlasMgr;
 };