Fix FakeNetworkPipe to not deliver packet faster than requested.

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 360b32ccf810a20b3e3f8fee88dc2f4e66aeb1ec..19f1b5451c82c99bf3bb9b3a2e7c1a9eca00e3d2 100644
--- a/webrtc/test/fake_network_pipe.cc
+++ b/webrtc/test/fake_network_pipe.cc
@@ -100,8 +100,9 @@ void FakeNetworkPipe::SendPacket(const uint8_t* data, size_t data_length) {
   int64_t network_start_time = time_now;
 
   // Check if there already are packets on the link and change network start
-  // time if there is.
-  if (!capacity_link_.empty())
+  // time forward if there is.
+  if (!capacity_link_.empty() &&
+      network_start_time < capacity_link_.back()->arrival_time())
     network_start_time = capacity_link_.back()->arrival_time();
 
   int64_t arrival_time = network_start_time + capacity_delay_ms;