Remove unpremul/remul from SkArithmeticMode, both raster and GPU, since the SVG spec actually defin…

gm/arithmode.cpp

 /*
  * Copyright 2011 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 "SkCanvas.h"
 #include "SkColorPriv.h"
@@ skipping 93 matching lines @@
         SkScalar gap = SkIntToScalar(src.width() + 20);
         while (k < stop) {
             SkScalar x = 0;
             canvas->drawBitmap(src, x, y, NULL);
             x += gap;
             canvas->drawBitmap(dst, x, y, NULL);
             x += gap;
             SkRect rect = SkRect::MakeXYWH(x, y, SkIntToScalar(WW), SkIntToScalar(HH));
             canvas->saveLayer(&rect, NULL);
             canvas->drawBitmap(dst, x, y, NULL);
-            SkXfermode* xfer = SkArithmeticMode::Create(k[0], k[1], k[2], k[3]);
+            SkXfermode* xfer = SkArithmeticMode::Create(k[0], k[1], k[2], k[3], true);
             SkPaint paint;
             paint.setXfermode(xfer)->unref();
             canvas->drawBitmap(src, x, y, &paint);
             canvas->restore();
             x += gap;
             show_k_text(canvas, x, y, k);
             k += 4;
             y += SkIntToScalar(src.height() + 12);
         }
     }
 
 private:
     typedef GM INHERITED;
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 
 static skiagm::GM* MyFactory(void*) { return new ArithmodeGM; }
 static skiagm::GMRegistry reg(MyFactory);