[native] Update GrDirectContext calls to use safer API

In http://review.skia.org/751523, Skia modified some GrDirectContext
APIs to make them less error-prone in response to https://crbug.com/1475906.

This updates part of Android to call those modified APIs.

Change-Id: Ib19a39cf937ba359b55c600a68a8f1c2266fd35a