Fix compile when SK_XML undefined

Change-Id: Ia23b07434939acbf544854b94c4b10810c20ae1a
Reviewed-on: https://skia-review.googlesource.com/131221
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Hal Canary <halcanary@google.com>
2 files changed