Auto merge of #974 - glennw:android-build-fix, r=pcwalton
Auto merge of #974 - glennw:android-build-fix, r=pcwalton

Fix android build error.

<!-- Reviewable:start -->
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/webrender/974)
<!-- Reviewable:end -->

servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender,servo/webrender