make pixelsnap textblob* etc gm portable

TBR=reed@google.com

Review URL: https://codereview.chromium.org/1263553002
diff --git a/gm/strokerect.cpp b/gm/strokerect.cpp
index 8854c6b..c190495 100644
--- a/gm/strokerect.cpp
+++ b/gm/strokerect.cpp
@@ -17,7 +17,7 @@
     paint.setAntiAlias(true);
     paint.setStyle(doFill ? SkPaint::kStrokeAndFill_Style : SkPaint::kStroke_Style);
 
-    paint.setColor(SK_ColorGRAY);
+    paint.setColor(sk_tool_utils::color_to_565(SK_ColorGRAY));
     paint.setStrokeWidth(STROKE_WIDTH);
     paint.setStrokeJoin(join);
     canvas->drawRect(rect, paint);