Fix issue where the number of packets reported in tests/simulations sometimes are negative.

BUG=webrtc:6159

Review-Url: https://codereview.webrtc.org/2223033002
Cr-Commit-Position: refs/heads/master@{#13850}
diff --git a/webrtc/modules/bitrate_controller/bitrate_controller_unittest.cc b/webrtc/modules/bitrate_controller/bitrate_controller_unittest.cc
index b40332e..a70eecf 100644
--- a/webrtc/modules/bitrate_controller/bitrate_controller_unittest.cc
+++ b/webrtc/modules/bitrate_controller/bitrate_controller_unittest.cc
@@ -152,14 +152,14 @@
   time_ms += 1000;
 
   report_blocks.clear();
-  report_blocks.push_back(CreateReportBlock(1, 2, 0, 801));
+  report_blocks.push_back(CreateReportBlock(1, 2, 0, 101));
   bandwidth_observer_->OnReceivedRtcpReceiverReport(report_blocks, 50, time_ms);
   EXPECT_EQ(299732, bitrate_observer_.last_bitrate_);
   time_ms += 1000;
 
   // Reach max cap.
   report_blocks.clear();
-  report_blocks.push_back(CreateReportBlock(1, 2, 0, 101));
+  report_blocks.push_back(CreateReportBlock(1, 2, 0, 121));
   bandwidth_observer_->OnReceivedRtcpReceiverReport(report_blocks, 50, time_ms);
   EXPECT_EQ(300000, bitrate_observer_.last_bitrate_);
   time_ms += 1000;