Convert GrClip to an abstract base class

tests/TessellatingPathRendererTests.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPath.h"
 
 #if SK_SUPPORT_GPU
@@ skipping 221 matching lines @@
     return path;
 }
 
 static void test_path(GrDrawTarget* dt, GrRenderTarget* rt, GrResourceProvider* rp,
                       const SkPath& path) {
     GrTessellatingPathRenderer tess;
     GrPipelineBuilder pipelineBuilder;
     pipelineBuilder.setXPFactory(
         GrPorterDuffXPFactory::Create(SkXfermode::kSrc_Mode))->unref();
     pipelineBuilder.setRenderTarget(rt);
+    GrNoClip noClip;
     GrStyle style(SkStrokeRec::kFill_InitStyle);
     GrPathRenderer::DrawPathArgs args;
     args.fTarget = dt;
     args.fPipelineBuilder = &pipelineBuilder;
-    args.fClip = &GrClip::WideOpen();
+    args.fClip = &noClip;
     args.fResourceProvider = rp;
     args.fColor = GrColor_WHITE;
     args.fViewMatrix = &SkMatrix::I();
     args.fPath = &path;
     args.fStyle = &style;
     args.fAntiAlias = false;
     tess.drawPath(args);
 }
 
 DEF_GPUTEST_FOR_ALL_CONTEXTS(TessellatingPathRendererTests, reporter, ctxInfo) {
@@ skipping 22 matching lines @@
     test_path(dt, rt, rp, create_path_8());
     test_path(dt, rt, rp, create_path_9());
     test_path(dt, rt, rp, create_path_10());
     test_path(dt, rt, rp, create_path_11());
     test_path(dt, rt, rp, create_path_12());
     test_path(dt, rt, rp, create_path_13());
     test_path(dt, rt, rp, create_path_14());
     test_path(dt, rt, rp, create_path_15());
 }
 #endif