Use RateCounter for received bitrate stats.

webrtc/video/stats_counter_unittest.cc

 /*
  *  Copyright (c) 2016 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.
  */
 
@@ skipping 54 matching lines @@
 TEST_F(StatsCounterTest, TestRegisterObserver) {
   StatsCounterObserverImpl* observer = new StatsCounterObserverImpl();
   const int kSample = 22;
   AvgCounter counter(&clock_, observer);
   AddSampleAndAdvance(kSample, kProcessIntervalMs, &counter);
   // Trigger process (sample included in next interval).
   counter.Add(111);
   EXPECT_EQ(1, observer->num_calls_);
 }
 
+TEST_F(StatsCounterTest, HasSample) {
+  AvgCounter counter(&clock_, nullptr);
+  EXPECT_FALSE(counter.HasSample());
+  counter.Add(1);
+  EXPECT_TRUE(counter.HasSample());
+}
+
 TEST_F(StatsCounterTest, VerifyProcessInterval) {
   StatsCounterObserverImpl* observer = new StatsCounterObserverImpl();
   AvgCounter counter(&clock_, observer);
   counter.Add(4);
   clock_.AdvanceTimeMilliseconds(kProcessIntervalMs - 1);
   // Try trigger process (interval has not passed).
   counter.Add(8);
   EXPECT_EQ(0, observer->num_calls_);
   VerifyStatsIsNotSet(counter.GetStats());
   // Make process interval pass.
@@ skipping 253 matching lines @@
   EXPECT_EQ(3, observer->num_calls_);
   EXPECT_EQ(10, observer->last_sample_);
   // Aggregated stats.
   AggregatedStats stats = counter.GetStats();
   EXPECT_EQ(3, stats.num_samples);
   EXPECT_EQ(0, stats.min);
   EXPECT_EQ(25, stats.max);
 }
 
 }  // namespace webrtc