Fix off-by-one error in PRNG.

webrtc/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_TEST_RANDOM_H_
 #define WEBRTC_TEST_RANDOM_H_
 
 #include "webrtc/typedefs.h"
 #include "webrtc/base/constructormagic.h"
 
 namespace webrtc {
 
 namespace test {
 
 class Random {
  public:
   explicit Random(uint32_t seed);
 
-  // Return pseudo-random number in the interval [0.0, 1.0].
+  // Return pseudo-random number in the interval [0.0, 1.0).
   float Rand();
 
-  // Return pseudo rounded random number in interval [low, high].
+  // Return pseudo-random number mapped to the interval [low, high].
   int Rand(int low, int high);
 
   // Normal Distribution.
   int Gaussian(int mean, int standard_deviation);
 
   // Exponential Distribution.
   int Exponential(float lambda);
 
   // 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 test
 }  // namespace webrtc
 
 #endif  // WEBRTC_TEST_RANDOM_H_