Skia color space fuzzer: use a locally defined Hash function

testing/libfuzzer/fuzzers/skia_color_space_fuzzer.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <cstddef>
 #include <cstdint>
 #include <random>
 
 #include "base/logging.h"
-#include "base/strings/string_piece.h"
 #include "testing/libfuzzer/fuzzers/color_space_data.h"
 #include "third_party/skia/include/core/SkColorSpace.h"
 #include "third_party/skia/include/core/SkColorSpaceXform.h"
 
 static constexpr size_t kPixels = 2048 / 4;
 
 static uint32_t pixels[kPixels * 4];
 
 static void GeneratePixels(size_t hash) {
   static std::uniform_int_distribution<uint32_t> uniform(0u, ~0u);
@@ skipping 35 matching lines @@
           SkColorSpace::Gamut::kAdobeRGB_Gamut),
       SkColorSpace::MakeRGB(
           SkColorSpace::RenderTargetGamma::kSRGB_RenderTargetGamma,
           SkColorSpace::Gamut::kDCIP3_D65_Gamut),
       SkColorSpace::MakeSRGB(),
   };
 
   return profiles[hash & 7];
 }
 
-inline size_t Hash(const char* data, size_t size) {
-  return base::StringPieceHash()(base::StringPiece(data, size));
+inline size_t Hash(const char* data, size_t size, size_t hash = ~0) {
+  for (size_t i = 0; i < size; ++i)
+    hash = hash * 131 + *data++;
+  return hash;
 }
 
 extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
   constexpr size_t kSizeLimit = 4 * 1024 * 1024;
   if (size < 128 || size > kSizeLimit)
     return 0;
 
   test = SkColorSpace::MakeICC(data, size);
   if (!test.get())
     return 0;
 
   const size_t hash = Hash(reinterpret_cast<const char*>(data), size);
   srgb = SelectProfile(hash);
   GeneratePixels(hash);
 
   ColorTransform(hash, true);
   ColorTransform(hash, false);
 
   test.reset();
   srgb.reset();
   return 0;
 }