move SkDither.h to private, remove unused shadeSpan16

src/effects/SkPerlinNoiseShader.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 "SkDither.h"
 #include "SkPerlinNoiseShader.h"
 #include "SkColorFilter.h"
 #include "SkReadBuffer.h"
 #include "SkWriteBuffer.h"
 #include "SkShader.h"
 #include "SkUnPreMultiply.h"
 #include "SkString.h"
 
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
@@ skipping 441 matching lines @@
 void SkPerlinNoiseShader::PerlinNoiseShaderContext::shadeSpan(
         int x, int y, SkPMColor result[], int count) {
     SkPoint point = SkPoint::Make(SkIntToScalar(x), SkIntToScalar(y));
     StitchData stitchData;
     for (int i = 0; i < count; ++i) {
         result[i] = shade(point, stitchData);
         point.fX += SK_Scalar1;
     }
 }
 
-void SkPerlinNoiseShader::PerlinNoiseShaderContext::shadeSpan16(
-        int x, int y, uint16_t result[], int count) {
-    SkPoint point = SkPoint::Make(SkIntToScalar(x), SkIntToScalar(y));
-    StitchData stitchData;
-    DITHER_565_SCAN(y);
-    for (int i = 0; i < count; ++i) {
-        unsigned dither = DITHER_VALUE(x);
-        result[i] = SkDitherRGB32To565(shade(point, stitchData), dither);
-        DITHER_INC_X(x);
-        point.fX += SK_Scalar1;
-    }
-}
-
 /////////////////////////////////////////////////////////////////////
 
 #if SK_SUPPORT_GPU
 
 class GrGLPerlinNoise : public GrGLSLFragmentProcessor {
 public:
     GrGLPerlinNoise(const GrProcessor&);
     virtual ~GrGLPerlinNoise() {}
 
     virtual void emitCode(EmitArgs&) override;
@@ skipping 503 matching lines @@
     str->append(" seed: ");
     str->appendScalar(fSeed);
     str->append(" stitch tiles: ");
     str->append(fStitchTiles ? "true " : "false ");
 
     this->INHERITED::toString(str);
 
     str->append(")");
 }
 #endif