Implement network performance simulation for remoting perf tests.

remoting/test/leaky_bucket.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "remoting/test/leaky_bucket.h"
+
+#include "base/logging.h"
+
+namespace remoting {
+
+LeakyBucket::LeakyBucket(double depth, double rate)
+    : depth_(depth),
+      rate_(rate),
+      level_(0.0),
+      last_update_(base::TimeTicks::Now()) {
+}
+
+LeakyBucket::~LeakyBucket() {
+}
+
+base::TimeDelta LeakyBucket::AddPacket(int size) {
+  UpdateLevel();
+
+  double new_level = level_ + size;
+  if (new_level > depth_)
+    return base::TimeDelta::Max();
+
+  base::TimeDelta result = base::TimeDelta::FromSecondsD(level_ / rate_);
+  level_ = new_level;
+  return result;
+}
+
+void LeakyBucket::UpdateLevel() {
+  base::TimeTicks now = base::TimeTicks::Now();
+  level_ -= rate_ * (now - last_update_).InSecondsF();
+  if (level_ < 0.0)
+    level_ = 0.0;
+  last_update_ = now;
+}
+
+}  // namespace remoting