Move PRNG from BWE test framework to webrtc/test.

webrtc/modules/remote_bitrate_estimator/test/random.cc

Index: webrtc/modules/remote_bitrate_estimator/test/random.cc
diff --git a/webrtc/modules/remote_bitrate_estimator/test/random.cc b/webrtc/modules/remote_bitrate_estimator/test/random.cc
deleted file mode 100644
index d803be063685887b238c4fbd40277cb52cd62e70..0000000000000000000000000000000000000000
--- a/webrtc/modules/remote_bitrate_estimator/test/random.cc
+++ /dev/null
@@ -1,41 +0,0 @@
-/*
- *  Copyright (c) 2015 The WebRTC 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 in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#include "webrtc/modules/remote_bitrate_estimator/test/random.h"
-
-#include <math.h>
-
-namespace webrtc {
-
-Random::Random(uint32_t seed) : a_(0x531FDB97 ^ seed), b_(0x6420ECA8 + seed) {
-}
-
-float Random::Rand() {
-  const float kScale = 1.0f / 0xffffffff;
-  float result = kScale * b_;
-  a_ ^= b_;
-  b_ += a_;
-  return result;
-}
-
-int Random::Gaussian(int mean, int standard_deviation) {
-  // Creating a Normal distribution variable from two independent uniform
-  // variables based on the Box-Muller transform, which is defined on the
-  // interval (0, 1], hence the mask+add below.
-  const double kPi = 3.14159265358979323846;
-  const double kScale = 1.0 / 0x80000000ul;
-  double u1 = kScale * ((a_ & 0x7ffffffful) + 1);
-  double u2 = kScale * ((b_ & 0x7ffffffful) + 1);
-  a_ ^= b_;
-  b_ += a_;
-  return static_cast<int>(
-      mean + standard_deviation * sqrt(-2 * log(u1)) * cos(2 * kPi * u2));
-}
-}  // namespace webrtc