Unblock DEPS roll by remove SkAutoTUnref from GrDrawContext

src/gpu/GrDrawContext.cpp

Index: src/gpu/GrDrawContext.cpp
diff --git a/src/gpu/GrDrawContext.cpp b/src/gpu/GrDrawContext.cpp
index 3fe3f867199f8ed990cc670288d9fb5b70cf0375..29318862cd0cb63bcd345b741d0a87a16c49913b 100644
--- a/src/gpu/GrDrawContext.cpp
+++ b/src/gpu/GrDrawContext.cpp
@@ -33,6 +33,10 @@ GrDrawContext::GrDrawContext(GrContext* context, GrDrawTarget* drawTarget)
     , fDrawTarget(SkRef(drawTarget)) {
 }
 
+GrDrawContext::~GrDrawContext() {
+    SkSafeUnref(fDrawTarget);
+}
+
 void GrDrawContext::copySurface(GrRenderTarget* dst, GrSurface* src,
                                 const SkIRect& srcRect, const SkIPoint& dstPoint) {
     if (!this->prepareToDraw(dst)) {