Convert GrClip to an abstract base class

src/effects/SkDisplacementMapEffect.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDisplacementMapEffect.h"
 
 #include "SkBitmap.h"
@@ skipping 324 matching lines @@
         SkMatrix matrix;
         matrix.setTranslate(-SkIntToScalar(colorBounds.x()), -SkIntToScalar(colorBounds.y()));
 
         sk_sp<GrDrawContext> drawContext(context->newDrawContext(SkBackingFit::kApprox,
                                                                  bounds.width(), bounds.height(),
                                                                  kSkia8888_GrPixelConfig));
         if (!drawContext) {
             return nullptr;
         }
 
-        drawContext->drawRect(GrClip::WideOpen(), paint, matrix, SkRect::Make(colorBounds));
+        drawContext->drawRect(GrNoClip(), paint, matrix, SkRect::Make(colorBounds));
 
         offset->fX = bounds.left();
         offset->fY = bounds.top();
         return SkSpecialImage::MakeFromGpu(SkIRect::MakeWH(bounds.width(), bounds.height()),
                                            kNeedNewImageUniqueID_SpecialImage,
                                            drawContext->asTexture());
     }
 #endif
 
     SkBitmap colorBM, displBM;
@@ skipping 261 matching lines @@
 void GrGLDisplacementMapEffect::GenKey(const GrProcessor& proc,
                                        const GrGLSLCaps&, GrProcessorKeyBuilder* b) {
     const GrDisplacementMapEffect& displacementMap = proc.cast<GrDisplacementMapEffect>();
 
     uint32_t xKey = displacementMap.xChannelSelector();
     uint32_t yKey = displacementMap.yChannelSelector() << kChannelSelectorKeyBits;
 
     b->add32(xKey | yKey);
 }
 #endif