Improve bitrate probing for the audio-only case.

webrtc/modules/congestion_controller/delay_based_bwe_unittest.cc

Index: webrtc/modules/congestion_controller/delay_based_bwe_unittest.cc
diff --git a/webrtc/modules/congestion_controller/delay_based_bwe_unittest.cc b/webrtc/modules/congestion_controller/delay_based_bwe_unittest.cc
index d4b3a72a3fdebab7e1db3d6dac917543518d3b0c..4f0829ac6291feb1d8043d8be25c4439dc49b1c8 100644
--- a/webrtc/modules/congestion_controller/delay_based_bwe_unittest.cc
+++ b/webrtc/modules/congestion_controller/delay_based_bwe_unittest.cc
@@ -57,9 +57,7 @@ TEST_F(DelayBasedBweTest, ProbeDetectionNonPacedPackets) {
     IncomingFeedback(now_ms, now_ms, seq_num++, 1000, 0);
     // Non-paced packet, arriving 5 ms after.
     clock_.AdvanceTimeMilliseconds(5);
-    IncomingFeedback(now_ms, now_ms, seq_num++,
-                     PacedSender::kMinProbePacketSize + 1,
-                     PacketInfo::kNotAProbe);
+    IncomingFeedback(now_ms, now_ms, seq_num++, 100, PacketInfo::kNotAProbe);
   }
 
   EXPECT_TRUE(bitrate_observer_.updated());