Add constant for blitter context size.

bench/SkLinearBitmapPipelineBench.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 <memory>
 #include "SkColor.h"
 #include "SkLinearBitmapPipeline.h"
+#include "SkBitmapProcShader.h"
 #include "SkPM4f.h"
 #include "Benchmark.h"
 #include "SkShader.h"
 #include "SkImage.h"
 
 struct CommonBitmapFPBenchmark : public Benchmark {
     CommonBitmapFPBenchmark(
         SkISize srcSize,
         SkColorProfileType colorProfile,
         SkMatrix m,
@@ skipping 165 matching lines @@
     void onPostDraw(SkCanvas*) override {
 
     }
 
     void onDraw(int loops, SkCanvas*) override {
         int width = fSrcSize.fWidth;
         int height = fSrcSize.fHeight;
 
         SkAutoTMalloc<SkPMColor> buffer4b(width*height);
 
-        uint32_t storage[300];
+        uint32_t storage[kSkBlitterContextSize];
         const SkShader::ContextRec rec(fPaint, fM, nullptr,
                                        SkShader::ContextRec::kPMColor_DstType);
         SkASSERT(fPaint.getShader()->contextSize(rec) <= sizeof(storage));
         SkShader::Context* ctx = fPaint.getShader()->createContext(rec, storage);
 
         int count = 100;
 
         for (int n = 0; n < 1000*loops; n++) {
             ctx->shadeSpan(3, 6, buffer4b, count);
         }
@@ skipping 128 matching lines @@
     srcSize, kSRGB_SkColorProfileType, mR, true,
     SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode);)
 
 DEF_BENCH(return new SkBitmapFPGeneral(
     srcSize, kLinear_SkColorProfileType, mR, true,
     SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode);)
 
 DEF_BENCH(return new SkBitmapFPOrigShader(
     srcSize, kLinear_SkColorProfileType, mR, true,
     SkShader::kRepeat_TileMode, SkShader::kRepeat_TileMode);)