Change to use local Random object instead of global rand() in the RtcEventLog unit test.

webrtc/test/random.cc

Index: webrtc/test/random.cc
diff --git a/webrtc/test/random.cc b/webrtc/test/random.cc
index c4c405f6b8884732de3d3bc7e95ddb80f026190a..211439b6447309bcc9d2165ee65b60f73624c743 100644
--- a/webrtc/test/random.cc
+++ b/webrtc/test/random.cc
@@ -29,10 +29,18 @@ float Random::Rand() {
   return static_cast<float>(result);
 }

[stefan-webrtc, 2015/10/22 09:41:22]

Should this be implemented using Uniform() instead?

[the sun, 2015/10/22 12:30:38]

Maybe the a_ ^= b_; b_ += a_; part could be put in an internal helper uint32_t
Next()?

However, I'm fine duplicating the code as well. Your call.

[terelius, 2015/10/26 18:18:41]

Using Uniform(MAX_INT) would give the exact same result as the current code, but
requires 64-bit arithmetic. I think it is better to keep it as it is for now.

[terelius, 2015/10/26 18:18:41]

Considering it is only 2 simple lines I think it is fine to duplicate them here.
When I rewrite the PRNG to use an xorshift* algorithm I'll make sure to add a
helper function to advance the state though.

 
-int Random::Rand(int low, int high) {
+uint32_t Random::Uniform(uint32_t t) {
+  uint64_t result = t;
+  result = b_ * (result + 1);
+  result = result >> 32;

[the sun, 2015/10/22 12:30:38]

Nice!

+  a_ ^= b_;
+  b_ += a_;
+  return result;
+}
+
+uint32_t Random::Uniform(uint32_t low, uint32_t high) {
   RTC_DCHECK(low <= high);
-  float uniform = Rand() * (high - low + 1) + low;
-  return static_cast<int>(uniform);
+  return Uniform(high - low) + low;
 }
 
 int Random::Gaussian(int mean, int standard_deviation) {