Convert GrClip to an abstract base class

src/gpu/GrDrawContextPriv.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrDrawContextPriv_DEFINED
 #define GrDrawContextPriv_DEFINED
 
 #include "GrDrawContext.h"
 
+class GrFixedClip;
 struct GrUserStencilSettings;
 
 /** Class that adds methods to GrDrawContext that are only intended for use internal to Skia.
     This class is purely a privileged window into GrDrawContext. It should never have additional
     data members or virtual methods. */
 class GrDrawContextPriv {
 public:
-    bool drawAndStencilRect(const GrClip&,
+    bool drawAndStencilRect(const GrFixedClip&,
                             const GrUserStencilSettings*,
                             SkRegion::Op op,
                             bool invert,
                             bool doAA,
                             const SkMatrix& viewMatrix,
                             const SkRect&);
 
-    bool drawAndStencilPath(const GrClip&,
+    bool drawAndStencilPath(const GrFixedClip&,
                             const GrUserStencilSettings*,
                             SkRegion::Op op,
                             bool invert,
                             bool doAA,
                             const SkMatrix& viewMatrix,
                             const SkPath&);
 
     void testingOnly_drawBatch(const GrPipelineBuilder& pipelineBuilder,
                                GrDrawBatch* batch,
                                const GrClip* = nullptr);
@@ skipping 12 matching lines @@
     friend class GrDrawContext; // to construct/copy this type.
 };
 
 inline GrDrawContextPriv GrDrawContext::drawContextPriv() { return GrDrawContextPriv(this); }
 
 inline const GrDrawContextPriv GrDrawContext::drawContextPriv () const {
     return GrDrawContextPriv(const_cast<GrDrawContext*>(this));
 }
 
 #endif