Move PRNG from BWE test framework to webrtc/test.

webrtc/modules/remote_bitrate_estimator/test/random.h

-/*
- *  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.
- */
-
-#ifndef WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_TEST_RANDOM_H_
-#define WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_TEST_RANDOM_H_
-
-#include "webrtc/typedefs.h"
-#include "webrtc/base/constructormagic.h"
-
-namespace webrtc {
-
-class Random {
- public:
-  explicit Random(uint32_t seed);
-
-  // Return pseudo-random number in the interval [0.0, 1.0].
-  float Rand();
-
-  // Normal Distribution.
-  int Gaussian(int mean, int standard_deviation);
-
-  // TODO(solenberg): Random from histogram.
-  // template<typename T> int Distribution(const std::vector<T> histogram) {
-
- private:
-  uint32_t a_;
-  uint32_t b_;
-
-  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(Random);
-};
-}  // namespace webrtc
-
-#endif  // WEBRTC_MODULES_REMOTE_BITRATE_ESTIMATOR_TEST_RANDOM_H_