Flush denorm half floats to zero.

src/core/SkLinearBitmapPipeline_sample.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkLinearBitmapPipeline_sampler_DEFINED
 #define SkLinearBitmapPipeline_sampler_DEFINED
 
@@ skipping 167 matching lines @@
     }
 };
 
 template <>
 class PixelConverter<kRGBA_F16_SkColorType, kLinear_SkGammaType> {
 public:
     using Element = uint64_t;
     PixelConverter(const SkPixmap& srcPixmap) { }
 
     Sk4f toSk4f(const Element pixel) const {
-        return SkHalfToFloat_finite(pixel);
+        return SkHalfToFloat_finite_ftz(pixel);
     }
 };
 
 class PixelAccessorShim {
 public:
     explicit PixelAccessorShim(SkLinearBitmapPipeline::PixelAccessorInterface* accessor)
         : fPixelAccessor(accessor) { }
 
     void SK_VECTORCALL getFewPixels(
         int n, Sk4i xs, Sk4i ys, Sk4f* px0, Sk4f* px1, Sk4f* px2) const {
@@ skipping 828 matching lines @@
     const SkShader::TileMode fXEdgeType;
     const int                fXMax;
     const SkShader::TileMode fYEdgeType;
     const int                fYMax;
     Accessor                 fAccessor;
 };
 
 }  // namespace
 
 #endif  // SkLinearBitmapPipeline_sampler_DEFINED