Bring sk_sp to GrDrawContext

src/gpu/GrRenderTarget.cpp

Index: src/gpu/GrRenderTarget.cpp
diff --git a/src/gpu/GrRenderTarget.cpp b/src/gpu/GrRenderTarget.cpp
index ae44071976bd36fc5e0e3258d0ea1c64fef7471a..a6736403fce612d2f91b2feca254455aef3341e9 100644
--- a/src/gpu/GrRenderTarget.cpp
+++ b/src/gpu/GrRenderTarget.cpp
@@ -29,7 +29,7 @@ void GrRenderTarget::discard() {
         return;
     }
 
-    SkAutoTUnref<GrDrawContext> drawContext(context->drawContext(this));
+    sk_sp<GrDrawContext> drawContext(context->drawContext(sk_ref_sp(this)));
     if (!drawContext) {
         return;
     }