Add dest type hint to SkShader::ContextRec

gm/SkLinearBitmapPipelineGM.cpp

 /*
  * Copyright 2016 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 "SkBlitter.h"
 #include "SkCanvas.h"
 #include "SkColor.h"
 #include "SkImage.h"
 #include "SkImageInfo.h"
 #include "SkLinearBitmapPipeline.h"
 #include "SkXfermode.h"
 #include "SkPM4fPriv.h"
 #include "SkShader.h"
 
 static void fill_in_bits(SkBitmap& bm, SkIRect ir, SkColor c, bool premul) {
@@ skipping 41 matching lines @@
         info, pmsrc.addr32(), pmsrc.rowBytes())};
     SkPaint paint;
     int32_t storage[200];
     SkShader* shader = image->newShader(SkShader::kClamp_TileMode, SkShader::kClamp_TileMode);
     if (useBilerp) {
         paint.setFilterQuality(SkFilterQuality::kLow_SkFilterQuality);
     } else {
         paint.setFilterQuality(SkFilterQuality::kNone_SkFilterQuality);
     }
     paint.setShader(shader)->unref();
-    const SkShader::ContextRec rec(paint, *mat, nullptr);
+    const SkShader::ContextRec rec(paint, *mat, nullptr,
+                                   SkBlitter::PreferredShaderDest(pmsrc.info()));
     SkASSERT(paint.getShader()->contextSize(rec) <= sizeof(storage));
 
     SkShader::Context* ctx = paint.getShader()->createContext(rec, storage);
 
     for (int y = 0; y < ir.height(); y++) {
         ctx->shadeSpan(0, y, pmdst.writable_addr32(0, y), ir.width());
     }
 
     canvas->drawBitmap(bmdst, r.left(), r.top(), nullptr);
 
@@ skipping 106 matching lines @@
             }
             canvas->restore();
             canvas->translate(0, H + 20);
         }
         canvas->restore();
         canvas->translate(0, (H + 20) * SK_ARRAY_COUNT(mats));
         if (useBilerp) break;
         useBilerp = true;
     }
 }