Keep track of the capacity delay error in the FakeNetworkPipe.

webrtc/test/fake_network_pipe.cc

Index: webrtc/test/fake_network_pipe.cc
diff --git a/webrtc/test/fake_network_pipe.cc b/webrtc/test/fake_network_pipe.cc
index bb9d6b1322e5ecf495aca3b46ec25c098bed2d98..61ac91858c642980416082ee409a339e15b58556 100644
--- a/webrtc/test/fake_network_pipe.cc
+++ b/webrtc/test/fake_network_pipe.cc
@@ -132,8 +132,16 @@ void FakeNetworkPipe::SendPacket(const uint8_t* data, size_t data_length) {
 
   // Delay introduced by the link capacity.
   int64_t capacity_delay_ms = 0;
-  if (config_.link_capacity_kbps > 0)
-    capacity_delay_ms = data_length / (config_.link_capacity_kbps / 8);
+  if (config_.link_capacity_kbps > 0) {
+    const int bytes_per_millisecond = config_.link_capacity_kbps / 8;

[terelius, 2017/09/04 12:19:39]

nit: Would bytes_per_ms make the capacity_delay calculation fit on two lines?

+    // To round to the closest millisecond we add half a milliseconds worth of
+    // bytes to the delay calculation.
+    capacity_delay_ms = (data_length + capacity_delay_error_bytes_ +
+                         bytes_per_millisecond / 2) /
+                        bytes_per_millisecond;
+    capacity_delay_error_bytes_ +=
+        data_length - capacity_delay_ms * bytes_per_millisecond;
+  }
   int64_t network_start_time = time_now;
 
   // Check if there already are packets on the link and change network start