Don't initiate perodic probing if we don't have a bandwidth estimate.

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 157 matching lines @@
 
   EXPECT_CALL(pacer_, CreateProbeCluster(_)).Times(1);
   EXPECT_CALL(pacer_, GetApplicationLimitedRegionStartTime())
       .WillRepeatedly(Return(rtc::Optional<int64_t>(start_time)));
   clock_.AdvanceTimeMilliseconds(1000);
   probe_controller_->Process();
   probe_controller_->SetEstimatedBitrate(500);
   testing::Mock::VerifyAndClearExpectations(&pacer_);
 }
 
+TEST_F(ProbeControllerTest, PeriodicProbingAfterReset) {
+  testing::StrictMock<MockPacedSender> local_pacer;
+  probe_controller_.reset(new ProbeController(&local_pacer, &clock_));
+  int64_t alr_start_time = clock_.TimeInMilliseconds();
+  EXPECT_CALL(local_pacer, GetApplicationLimitedRegionStartTime())
+      .WillRepeatedly(
+          Return(rtc::Optional<int64_t>(alr_start_time)));
+
+  EXPECT_CALL(local_pacer, CreateProbeCluster(_)).Times(2);
+  probe_controller_->EnablePeriodicAlrProbing(true);
+  probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
+                                 kMaxBitrateBps);
+  probe_controller_->Reset();
+
+  clock_.AdvanceTimeMilliseconds(10000);
+  probe_controller_->Process();
+
+  EXPECT_CALL(local_pacer, CreateProbeCluster(_)).Times(2);
+  probe_controller_->SetBitrates(kMinBitrateBps, kStartBitrateBps,
+                                 kMaxBitrateBps);
+
+  // Make sure we use |kStartBitrateBps| as the estimated bitrate
+  // until SetEstimatedBitrate is called with an updated estimate.
+  clock_.AdvanceTimeMilliseconds(10000);
+  EXPECT_CALL(local_pacer, CreateProbeCluster(kStartBitrateBps*2));
+  probe_controller_->Process();
+}
+
 TEST_F(ProbeControllerTest, TestExponentialProbingOverflow) {
   const int64_t kMbpsMultiplier = 1000000;
   probe_controller_->SetBitrates(kMinBitrateBps, 10 * kMbpsMultiplier,
                                  100 * kMbpsMultiplier);
 
   // Verify that probe bitrate is capped at the specified max bitrate
   EXPECT_CALL(pacer_, CreateProbeCluster(100 * kMbpsMultiplier));
   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