Replace RE2 import with a dependency

third_party/re2/util/random.cc

-// Copyright 2005-2009 The RE2 Authors.  All Rights Reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Modified from Google perftools's tcmalloc_unittest.cc.
-
-#include "util/random.h"
-
-namespace re2 {
-
-int32 ACMRandom::Next() {
-  const int32 M = 2147483647L;   // 2^31-1
-  const int32 A = 16807;
-  // In effect, we are computing seed_ = (seed_ * A) % M, where M = 2^31-1
-  uint32 lo = A * (int32)(seed_ & 0xFFFF);
-  uint32 hi = A * (int32)((uint32)seed_ >> 16);
-  lo += (hi & 0x7FFF) << 16;
-  if (lo > M) {
-    lo &= M;
-    ++lo;
-  }
-  lo += hi >> 15;
-  if (lo > M) {
-    lo &= M;
-    ++lo;
-  }
-  return (seed_ = (int32) lo);
-}
-
-int32 ACMRandom::Uniform(int32 n) {
-  return Next() % n;
-}
-
-}  // namespace re2