Unblock DEPS roll by remove SkAutoTUnref from GrDrawContext

include/gpu/GrDrawContext.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrDrawContext_DEFINED
 #define GrDrawContext_DEFINED
 
@@ skipping 208 matching lines @@
                   const GrPaint& paint,
                   const SkMatrix& viewMatrix,
                   const SkRect& oval,
                   const GrStrokeInfo& strokeInfo);
 
 
 private:
     friend class GrContext; // for ctor
 
     GrDrawContext(GrContext* context, GrDrawTarget* drawTarget);
+    ~GrDrawContext() override;
 
     // Sets the paint. Returns true on success; false on failure.
     bool prepareToDraw(GrPipelineBuilder*,
                        GrRenderTarget* rt,
                        const GrClip&,
                        const GrPaint* paint);
 
     // A simpler version of the above which just returns true on success; false on failure.  
     // Clip is *NOT* set
     bool prepareToDraw(GrRenderTarget* rt);
 
     void internalDrawPath(GrDrawTarget*,
                           GrPipelineBuilder*,
                           const SkMatrix& viewMatrix,
                           GrColor,
                           bool useAA,
                           const SkPath&,
                           const GrStrokeInfo&);
 
-    GrContext*                     fContext;     // owning context -> no ref
-    SkAutoTUnref<GrDrawTarget>     fDrawTarget;
+    GrContext*     fContext;     // owning context -> no ref
+    GrDrawTarget*  fDrawTarget;
 };
 
 #endif