Move SampleStatsCounter to public API

Bug: None
Change-Id: I8956f6febbb1caf71e951d212d57746fe1ec5eb2
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/184506
Commit-Queue: Artem Titov <titovartem@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32142}
diff --git a/rtc_base/random_unittest.cc b/rtc_base/random_unittest.cc
index f94b0c1..4eb6f75 100644
--- a/rtc_base/random_unittest.cc
+++ b/rtc_base/random_unittest.cc
@@ -120,7 +120,7 @@
 
   ASSERT_GE(high, low);
   ASSERT_GE(bucket_count, 2u);
-  uint32_t interval = unsigned_difference<int32_t>(high, low) + 1;
+  uint32_t interval = webrtc_impl::unsigned_difference<int32_t>(high, low) + 1;
   uint32_t numbers_per_bucket;
   if (interval == 0) {
     // The computation high - low + 1 should be 2^32 but overflowed
@@ -136,7 +136,8 @@
     int32_t sample = prng->Rand(low, high);
     EXPECT_LE(low, sample);
     EXPECT_GE(high, sample);
-    buckets[unsigned_difference<int32_t>(sample, low) / numbers_per_bucket]++;
+    buckets[webrtc_impl::unsigned_difference<int32_t>(sample, low) /
+            numbers_per_bucket]++;
   }
 
   for (unsigned int i = 0; i < bucket_count; i++) {