Hide fields in SkImageInfo

R=rmistry@google.com
TBR=bsalomon

Author: reed@google.com

Review URL: https://codereview.chromium.org/536003002
diff --git a/tests/BitmapCopyTest.cpp b/tests/BitmapCopyTest.cpp
index 6a20668..3923846 100644
--- a/tests/BitmapCopyTest.cpp
+++ b/tests/BitmapCopyTest.cpp
@@ -609,8 +609,8 @@
     for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); ++i) {
         clear_4x4_pixels(dstPixels);
 
-        dstInfo.fWidth = gRec[i].fRequestedDstSize.width();
-        dstInfo.fHeight = gRec[i].fRequestedDstSize.height();
+        dstInfo = dstInfo.makeWH(gRec[i].fRequestedDstSize.width(),
+                                 gRec[i].fRequestedDstSize.height());
         bool success = srcBM.readPixels(dstInfo, dstPixels, rowBytes,
                                         gRec[i].fRequestedSrcLoc.x(), gRec[i].fRequestedSrcLoc.y());