allow clip calls w/o op param, remove unnecessary kReplace ops

gm/pathopsskpclip.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 "gm.h"
 #include "SkBitmap.h"
 #include "SkCanvas.h"
@@ skipping 24 matching lines @@
         SkPictureRecorder recorder;
         SkCanvas* rec = recorder.beginRecording(1200, 900, nullptr, 0);
         SkPath p;
         SkRect r = {
             SkIntToScalar(100),
             SkIntToScalar(200),
             SkIntToScalar(400),
             SkIntToScalar(700)
         };
         p.addRoundRect(r, SkIntToScalar(50), SkIntToScalar(50));
-        rec->clipPath(p, SkCanvas::kIntersect_Op, true);
+        rec->clipPath(p, true);
         rec->translate(SkIntToScalar(250), SkIntToScalar(250));
-        rec->clipPath(p, SkCanvas::kIntersect_Op, true);
+        rec->clipPath(p, true);
         rec->drawColor(0xffff0000);
         sk_sp<SkPicture> pict(recorder.finishRecordingAsPicture());
 
         canvas->setAllowSimplifyClip(true);
         canvas->save();
         canvas->drawPicture(pict);
         canvas->restore();
 
         canvas->setAllowSimplifyClip(false);
         canvas->save();
         canvas->translate(SkIntToScalar(1200 / 2), 0);
         canvas->drawPicture(pict);
         canvas->restore();
     }
 
 private:
     typedef GM INHERITED;
 };
 
 //////////////////////////////////////////////////////////////////////////////
 
 static GM* MyFactory(void*) { return new PathOpsSkpClipGM; }
 static GMRegistry reg(MyFactory);
 
 }