revise row blits to keep intermediate precision so that color is preserved when blended against its…

gm/blend.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 "gm.h"
 
 DEF_SIMPLE_GM(blend, canvas, 300, 100) {
     SkPaint p;
 
     // All three of these blocks should be the same color.
     canvas->save();
         canvas->scale(100,100);
 
         p.setColor(SK_ColorRED);
         canvas->drawRect(SkRect::MakeXYWH(0,0,1,1), p);
-        p.setColor(0xFC008000);
+        p.setColor(0xFC208000);
         canvas->drawRect(SkRect::MakeXYWH(0,0,1,1), p);
 
         p.setColor(SK_ColorRED);
         canvas->drawRect(SkRect::MakeXYWH(1,0,1,1), p);
         canvas->saveLayer(nullptr, nullptr);
-            p.setColor(0xFC008000);
+            p.setColor(0xFC208000);
             canvas->drawRect(SkRect::MakeXYWH(1,0,1,1), p);
         canvas->restore();
 
         p.setColor(SK_ColorRED);
         canvas->drawRect(SkRect::MakeXYWH(2,0,1,1), p);
         canvas->saveLayerAlpha(nullptr, 0xFC);
-            p.setColor(sk_tool_utils::color_to_565(0xFF008000));
+            p.setColor(sk_tool_utils::color_to_565(0xFF208000));
             canvas->drawRect(SkRect::MakeXYWH(2,0,1,1), p);
         canvas->restore();
     canvas->restore();
 }