Initiate mid-call probing even if estimated bitrate is at max configured bitrate.

webrtc/modules/congestion_controller/probe_controller_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.
  */
 #include <memory>
@@ skipping 61 matching lines @@
   // Long enough to time out exponential probing.
   clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
   probe_controller_->SetEstimatedBitrate(kStartBitrateBps);
   probe_controller_->Process();
 
   EXPECT_CALL(pacer_, CreateProbeCluster(kMaxBitrateBps + 100));
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps + 100);
 }
 
+TEST_F(ProbeControllerTest, InitiatesProbingOnMaxBitrateIncreaseAtMaxBitrate) {
+  EXPECT_CALL(pacer_, CreateProbeCluster(_)).Times(AtLeast(2));
+  probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
+                                 kMaxBitrateBps);
+  // Long enough to time out exponential probing.
+  clock_.AdvanceTimeMilliseconds(kExponentialProbingTimeoutMs);
+  probe_controller_->SetEstimatedBitrate(kStartBitrateBps);
+  probe_controller_->Process();
+
+  probe_controller_->SetEstimatedBitrate(kMaxBitrateBps);
+  EXPECT_CALL(pacer_, CreateProbeCluster(kMaxBitrateBps + 100));
+  probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
+                                 kMaxBitrateBps + 100);
+}
+
 TEST_F(ProbeControllerTest, TestExponentialProbing) {
   probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
                                  kMaxBitrateBps);
 
   // Repeated probe should only be sent when estimated bitrate climbs above
   // 0.7 * 6 * kStartBitrateBps = 1260.
   EXPECT_CALL(pacer_, CreateProbeCluster(_)).Times(0);
   probe_controller_->SetEstimatedBitrate(1000);
   testing::Mock::VerifyAndClearExpectations(&pacer_);
 
@@ skipping 78 matching lines @@
   probe_controller_->SetEstimatedBitrate(60 * kMbpsMultiplier);
   testing::Mock::VerifyAndClearExpectations(&pacer_);
 
   // Verify that repeated probes aren't sent.
   EXPECT_CALL(pacer_, CreateProbeCluster(_)).Times(0);
   probe_controller_->SetEstimatedBitrate(100 * kMbpsMultiplier);
 }
 
 }  // namespace test
 }  // namespace webrtc