Fix FakeNetworkPipe to not deliver packet faster than requested.

webrtc/test/fake_network_pipe.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 82 matching lines @@
 
   int64_t time_now = clock_->TimeInMilliseconds();
 
   // 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);
   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;
   NetworkPacket* packet = new NetworkPacket(data, data_length, time_now,
                                             arrival_time);
   capacity_link_.push(packet);
 }
 
 float FakeNetworkPipe::PercentageLoss() {
   rtc::CritScope crit(&lock_);
@@ skipping 79 matching lines @@
 int64_t FakeNetworkPipe::TimeUntilNextProcess() const {
   rtc::CritScope crit(&lock_);
   const int64_t kDefaultProcessIntervalMs = 30;
   if (capacity_link_.empty() || delay_link_.empty())
     return kDefaultProcessIntervalMs;
   return std::max<int64_t>(next_process_time_ - clock_->TimeInMilliseconds(),
                            0);
 }
 
 }  // namespace webrtc