Fix BitrateProber to match the requested bitrate more precisely

webrtc/modules/pacing/paced_sender_unittest.cc

Index: webrtc/modules/pacing/paced_sender_unittest.cc
diff --git a/webrtc/modules/pacing/paced_sender_unittest.cc b/webrtc/modules/pacing/paced_sender_unittest.cc
index fc80a9881349af92e35c06ed51941a35e404a391..cde5fd1febe2a5d357d911b20f8f65eba87366a4 100644
--- a/webrtc/modules/pacing/paced_sender_unittest.cc
+++ b/webrtc/modules/pacing/paced_sender_unittest.cc
@@ -828,6 +828,7 @@ TEST_F(PacedSenderTest, ProbingWithInsertedPackets) {
               kFirstClusterBps, kBitrateProbingError);
   EXPECT_EQ(0, packet_sender.padding_sent());
 
+  clock_.AdvanceTimeMilliseconds(send_bucket_->TimeUntilNextProcess());
   start = clock_.TimeInMilliseconds();
   while (packet_sender.packets_sent() < 10) {
     int time_until_process = send_bucket_->TimeUntilNextProcess();
@@ -836,9 +837,9 @@ TEST_F(PacedSenderTest, ProbingWithInsertedPackets) {
   }
   packets_sent = packet_sender.packets_sent() - packets_sent;
   // Validate second cluster bitrate.
-  EXPECT_NEAR(
-      packets_sent * kPacketSize * 8000 / (clock_.TimeInMilliseconds() - start),
-      kSecondClusterBps, kBitrateProbingError);
+  EXPECT_NEAR((packets_sent - 1) * kPacketSize * 8000 /
+                  (clock_.TimeInMilliseconds() - start),
+              kSecondClusterBps, kBitrateProbingError);
 }
 
 TEST_F(PacedSenderTest, ProbingWithPaddingSupport) {