Add fuzzer for xxHash.

BUILD.gn

@@ -30,6 +30,7 @@ if (!build_with_chromium) {
     deps = [
       ":angle_shader_translator",
       ":translator_fuzzer",
+      ":xxhash_fuzzer",
       "//samples:all",
       "//src/tests:all",
     ]
@@ -208,6 +209,15 @@ angle_source_set("xxhash") {
   configs -= [ "${angle_root}:extra_warnings" ]
 }
 
+fuzzer_test("xxhash_fuzzer") {
+  sources = [
+    "src/common/third_party/xxhash/xxhash_fuzzer.cpp",
+  ]
+  deps = [
+    ":xxhash",
+  ]
+}
+
 angle_static_library("angle_common") {
   sources = libangle_common_sources
 

src/common/third_party/xxhash/xxhash_fuzzer.cpp

+//
+// Copyright 2019 The ANGLE Project Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// xxHash Fuzzer test:
+//      Integration with Chromium's libfuzzer for xxHash.
+
+#include <cstddef>
+#include <cstdint>
+#include <cstring>
+
+#include "xxhash.h"
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+#if !defined(XXH_NO_LONG_LONG)
+    // Test 64-bit hash.
+    size_t seedSize64 = sizeof(unsigned long long);
+    if (size < seedSize64)
+    {
+        XXH64(data, size, 0ull);
+    }
+    else
+    {
+        unsigned long long seed64;
+        memcpy(&seed64, data, seedSize64);
+        XXH64(&data[seedSize64], size - seedSize64, seed64);
+    }
+#endif  // !defined(XXH_NO_LONG_LONG)
+
+    // Test 32-bit hash.
+    size_t seedSize32 = sizeof(unsigned int);
+    if (size < seedSize32)
+    {
+        XXH64(data, size, 0ull);
+    }
+    else
+    {
+        unsigned long long seed32;
+        memcpy(&seed32, data, seedSize32);
+        XXH32(&data[seedSize32], size - seedSize32, seed32);
+    }
+
+    return 0;
+}