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

webrtc/modules/congestion_controller/probe_controller_unittest.cc

Index: webrtc/modules/congestion_controller/probe_controller_unittest.cc
diff --git a/webrtc/modules/congestion_controller/probe_controller_unittest.cc b/webrtc/modules/congestion_controller/probe_controller_unittest.cc
index 19a9039adafa111aee4591281b978f09ce80d915..4ed2deeed1fe06813b2c9971a7581cd9681320f1 100644
--- a/webrtc/modules/congestion_controller/probe_controller_unittest.cc
+++ b/webrtc/modules/congestion_controller/probe_controller_unittest.cc
@@ -175,6 +175,34 @@ TEST_F(ProbeControllerTest, PeriodicProbing) {
   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,