Remove //net (except for Android test stuff) and sdch

net/base/bandwidth_metrics.h

-// Copyright (c) 2011 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.
-
-#ifndef NET_BASE_BANDWIDTH_METRICS_H_
-#define NET_BASE_BANDWIDTH_METRICS_H_
-
-#include <list>
-
-#include "base/logging.h"
-#include "base/metrics/histogram.h"
-#include "base/time/time.h"
-
-namespace net {
-
-// Tracks statistics about the bandwidth metrics over time.  In order to
-// measure, this class needs to know when individual streams are in progress,
-// so that it can know when to discount idle time.  The BandwidthMetrics
-// is unidirectional - it should only be used to record upload or download
-// bandwidth, but not both.
-//
-// Note, the easiest thing to do is to just measure each stream and average
-// them or add them.  However, this does not work.  If multiple streams are in
-// progress concurrently, you have to look at the aggregate bandwidth at any
-// point in time.
-//
-//   Example:
-//      Imagine 4 streams opening and closing with overlapping time.
-//      We can't measure bandwidth by looking at any individual stream.
-//      We can only measure actual bandwidth by looking at the bandwidth
-//      across all open streams.
-//
-//         Time --------------------------------------->
-//         s1 +----------------+
-//         s2              +----------------+
-//         s3                            +--------------+
-//         s4                            +--------------+
-//
-// Example usage:
-//
-//   BandwidthMetrics tracker;
-//
-//   // When a stream is created
-//   tracker.StartStream();
-//
-//   // When data is transferred on any stream
-//   tracker.RecordSample(bytes);
-//
-//   // When the stream is finished
-//   tracker.StopStream();
-//
-// NOTE: This class is not thread safe.
-//
-class BandwidthMetrics {
- public:
-  BandwidthMetrics()
-      : num_streams_in_progress_(0),
-        num_data_samples_(0),
-        data_sum_(0.0),
-        bytes_since_last_start_(0) {
-  }
-
-  // Get the bandwidth.  Returns Kbps (kilo-bits-per-second).
-  double bandwidth() const {
-    return data_sum_ / num_data_samples_;
-  }
-
-  // Record that we've started a stream.
-  void StartStream() {
-    // If we're the only stream, we've finished some idle time.  Record a new
-    // timestamp to indicate the start of data flow.
-    if (++num_streams_in_progress_ == 1) {
-      last_start_ = base::TimeTicks::Now();
-      bytes_since_last_start_ = 0;
-    }
-  }
-
-  // Track that we've completed a stream.
-  void StopStream() {
-    if (--num_streams_in_progress_ == 0) {
-      // We don't use small streams when tracking bandwidth because they are not
-      // precise; imagine a 25 byte stream.  The sample is too small to make
-      // a good measurement.
-      // 20KB is an arbitrary value.  We might want to use a lesser value.
-      static const int64 kRecordSizeThreshold = 20 * 1024;
-      if (bytes_since_last_start_ < kRecordSizeThreshold)
-        return;
-
-      base::TimeDelta delta = base::TimeTicks::Now() - last_start_;
-      double ms = delta.InMillisecondsF();
-      if (ms > 0.0) {
-        double kbps = static_cast<double>(bytes_since_last_start_) * 8 / ms;
-        ++num_data_samples_;
-        data_sum_ += kbps;
-        VLOG(1) << "Bandwidth: " << kbps
-                << "Kbps (avg " << bandwidth() << "Kbps)";
-        int kbps_int = static_cast<int>(kbps);
-        UMA_HISTOGRAM_COUNTS_10000("Net.DownloadBandwidth", kbps_int);
-      }
-    }
-  }
-
-  // Add a sample of the number of bytes read from the network into the tracker.
-  void RecordBytes(int bytes) {
-    DCHECK(num_streams_in_progress_);
-    bytes_since_last_start_ += static_cast<int64>(bytes);
-  }
-
- private:
-  int num_streams_in_progress_;   // The number of streams in progress.
-  // TODO(mbelshe): Use a rolling buffer of 30 samples instead of an average.
-  int num_data_samples_;          // The number of samples collected.
-  double data_sum_;               // The sum of all samples collected.
-  int64 bytes_since_last_start_;  // Bytes tracked during this "session".
-  base::TimeTicks last_start_;    // Timestamp of the begin of this "session".
-};
-
-// A utility class for managing the lifecycle of a measured stream.
-// It is important that we not leave unclosed streams, and this class helps
-// ensure we always stop them.
-class ScopedBandwidthMetrics {
- public:
-  ScopedBandwidthMetrics();
-  ~ScopedBandwidthMetrics();
-
-  void StartStream();
-  void StopStream();
-  void RecordBytes(int bytes);
-
- private:
-  bool started_;
-};
-
-}  // namespace net
-
-#endif  // NET_BASE_BANDWIDTH_METRICS_H_