Pace outgoing frames in frame scheduler to match target bitrate.

remoting/base/leaky_bucket.cc

+// Copyright 2016 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/base/leaky_bucket.h"
+
+#include "base/logging.h"
+
+namespace remoting {
+
+LeakyBucket::LeakyBucket(int depth, int rate)
+    : depth_(depth),
+      rate_(rate),
+      current_level_(0),
+      level_updated_time_(base::TimeTicks::Now()) {}
+
+LeakyBucket::~LeakyBucket() {}
+
+bool LeakyBucket::RefillOrSpill(int drops, base::TimeTicks now) {
+  UpdateLevel(now);
+
+  int new_level = current_level_ + drops;
+  if (depth_ >= 0 && new_level > depth_)
+    return false;
+  current_level_ = new_level;
+  return true;
+}
+
+base::TimeTicks LeakyBucket::GetEmptyTime() {
+  return level_updated_time_ +
+         base::TimeDelta::FromMicroseconds(
+             base::TimeTicks::kMicrosecondsPerSecond * current_level_ / rate_);
+}
+
+void LeakyBucket::UpdateRate(int new_rate, base::TimeTicks now) {
+  UpdateLevel(now);
+  rate_ = new_rate;
+}
+
+void LeakyBucket::UpdateLevel(base::TimeTicks now) {
+  current_level_ -= rate_ * (now - level_updated_time_).InMicroseconds() /
+            base::TimeTicks::kMicrosecondsPerSecond;
+  if (current_level_ < 0)
+    current_level_ = 0;
+  level_updated_time_ = now;
+}
+
+}  // namespace remoting