Change SkPicture::draw to playback

R=reed@google.com

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/540963002
diff --git a/tests/SerializationTest.cpp b/tests/SerializationTest.cpp
index ea03e87..b5582dc 100644
--- a/tests/SerializationTest.cpp
+++ b/tests/SerializationTest.cpp
@@ -266,7 +266,7 @@
      bitmap.allocN32Pixels(SkScalarCeilToInt(picture.cullRect().width()), 
                            SkScalarCeilToInt(picture.cullRect().height()));
      SkCanvas canvas(bitmap);
-     picture.draw(&canvas);
+     picture.playback(&canvas);
      return bitmap;
 }