// Copyright 2018 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 "components/download/public/common//download_stats.h"

#include <map>

#include "base/callback.h"
#include "base/files/file_path.h"
#include "base/macros.h"
#include "base/metrics/histogram_functions.h"
#include "base/metrics/histogram_macros.h"
#include "base/strings/string_util.h"
#include "components/download/public/common/download_interrupt_reasons.h"
#include "net/http/http_content_disposition.h"
#include "net/http/http_util.h"

namespace download {

namespace {

// The maximium value for download deletion retention time histogram.
const int kMaxDeletionRetentionHours = 720;

// All possible error codes from the network module. Note that the error codes
// are all positive (since histograms expect positive sample values).
const int kAllInterruptReasonCodes[] = {
#define INTERRUPT_REASON(label, value) (value),
#include "components/download/public/common/download_interrupt_reason_values.h"
#undef INTERRUPT_REASON
};

// These values are based on net::HttpContentDisposition::ParseResult values.
// Values other than HEADER_PRESENT and IS_VALID are only measured if |IS_VALID|
// is true.
enum ContentDispositionCountTypes {
  // Count of downloads which had a Content-Disposition headers. The total
  // number of downloads is measured by UNTHROTTLED_COUNT.
  CONTENT_DISPOSITION_HEADER_PRESENT = 0,

  // Either 'filename' or 'filename*' attributes were valid and
  // yielded a non-empty filename.
  CONTENT_DISPOSITION_IS_VALID,

  // The following enum values correspond to
  // net::HttpContentDisposition::ParseResult.
  CONTENT_DISPOSITION_HAS_DISPOSITION_TYPE,
  CONTENT_DISPOSITION_HAS_UNKNOWN_TYPE,

  CONTENT_DISPOSITION_HAS_NAME,  // Obsolete; kept for UMA compatiblity.

  CONTENT_DISPOSITION_HAS_FILENAME,
  CONTENT_DISPOSITION_HAS_EXT_FILENAME,
  CONTENT_DISPOSITION_HAS_NON_ASCII_STRINGS,
  CONTENT_DISPOSITION_HAS_PERCENT_ENCODED_STRINGS,
  CONTENT_DISPOSITION_HAS_RFC2047_ENCODED_STRINGS,

  CONTENT_DISPOSITION_HAS_NAME_ONLY,  // Obsolete; kept for UMA compatiblity.

  CONTENT_DISPOSITION_LAST_ENTRY
};

void RecordContentDispositionCount(ContentDispositionCountTypes type,
                                   bool record) {
  if (!record)
    return;
  UMA_HISTOGRAM_ENUMERATION("Download.ContentDisposition", type,
                            CONTENT_DISPOSITION_LAST_ENTRY);
}

void RecordContentDispositionCountFlag(
    ContentDispositionCountTypes type,
    int flags_to_test,
    net::HttpContentDisposition::ParseResultFlags flag) {
  RecordContentDispositionCount(type, (flags_to_test & flag) == flag);
}

// Do not insert, delete, or reorder; this is being histogrammed. Append only.
// All of the download_file_types.asciipb entries should be in this list.
// TODO(asanka): Replace this enum with calls to FileTypePolicies and move the
// UMA metrics for dangerous/malicious downloads to //chrome/browser/download.
constexpr const base::FilePath::CharType* kDangerousFileTypes[] = {
    FILE_PATH_LITERAL(".ad"),          FILE_PATH_LITERAL(".ade"),
    FILE_PATH_LITERAL(".adp"),         FILE_PATH_LITERAL(".ah"),
    FILE_PATH_LITERAL(".apk"),         FILE_PATH_LITERAL(".app"),
    FILE_PATH_LITERAL(".application"), FILE_PATH_LITERAL(".asp"),
    FILE_PATH_LITERAL(".asx"),         FILE_PATH_LITERAL(".bas"),
    FILE_PATH_LITERAL(".bash"),        FILE_PATH_LITERAL(".bat"),
    FILE_PATH_LITERAL(".cfg"),         FILE_PATH_LITERAL(".chi"),
    FILE_PATH_LITERAL(".chm"),         FILE_PATH_LITERAL(".class"),
    FILE_PATH_LITERAL(".cmd"),         FILE_PATH_LITERAL(".com"),
    FILE_PATH_LITERAL(".command"),     FILE_PATH_LITERAL(".crt"),
    FILE_PATH_LITERAL(".crx"),         FILE_PATH_LITERAL(".csh"),
    FILE_PATH_LITERAL(".deb"),         FILE_PATH_LITERAL(".dex"),
    FILE_PATH_LITERAL(".dll"),         FILE_PATH_LITERAL(".drv"),
    FILE_PATH_LITERAL(".exe"),         FILE_PATH_LITERAL(".fxp"),
    FILE_PATH_LITERAL(".grp"),         FILE_PATH_LITERAL(".hlp"),
    FILE_PATH_LITERAL(".hta"),         FILE_PATH_LITERAL(".htm"),
    FILE_PATH_LITERAL(".html"),        FILE_PATH_LITERAL(".htt"),
    FILE_PATH_LITERAL(".inf"),         FILE_PATH_LITERAL(".ini"),
    FILE_PATH_LITERAL(".ins"),         FILE_PATH_LITERAL(".isp"),
    FILE_PATH_LITERAL(".jar"),         FILE_PATH_LITERAL(".jnlp"),
    FILE_PATH_LITERAL(".user.js"),     FILE_PATH_LITERAL(".js"),
    FILE_PATH_LITERAL(".jse"),         FILE_PATH_LITERAL(".ksh"),
    FILE_PATH_LITERAL(".lnk"),         FILE_PATH_LITERAL(".local"),
    FILE_PATH_LITERAL(".mad"),         FILE_PATH_LITERAL(".maf"),
    FILE_PATH_LITERAL(".mag"),         FILE_PATH_LITERAL(".mam"),
    FILE_PATH_LITERAL(".manifest"),    FILE_PATH_LITERAL(".maq"),
    FILE_PATH_LITERAL(".mar"),         FILE_PATH_LITERAL(".mas"),
    FILE_PATH_LITERAL(".mat"),         FILE_PATH_LITERAL(".mau"),
    FILE_PATH_LITERAL(".mav"),         FILE_PATH_LITERAL(".maw"),
    FILE_PATH_LITERAL(".mda"),         FILE_PATH_LITERAL(".mdb"),
    FILE_PATH_LITERAL(".mde"),         FILE_PATH_LITERAL(".mdt"),
    FILE_PATH_LITERAL(".mdw"),         FILE_PATH_LITERAL(".mdz"),
    FILE_PATH_LITERAL(".mht"),         FILE_PATH_LITERAL(".mhtml"),
    FILE_PATH_LITERAL(".mmc"),         FILE_PATH_LITERAL(".mof"),
    FILE_PATH_LITERAL(".msc"),         FILE_PATH_LITERAL(".msh"),
    FILE_PATH_LITERAL(".mshxml"),      FILE_PATH_LITERAL(".msi"),
    FILE_PATH_LITERAL(".msp"),         FILE_PATH_LITERAL(".mst"),
    FILE_PATH_LITERAL(".ocx"),         FILE_PATH_LITERAL(".ops"),
    FILE_PATH_LITERAL(".pcd"),         FILE_PATH_LITERAL(".pif"),
    FILE_PATH_LITERAL(".pkg"),         FILE_PATH_LITERAL(".pl"),
    FILE_PATH_LITERAL(".plg"),         FILE_PATH_LITERAL(".prf"),
    FILE_PATH_LITERAL(".prg"),         FILE_PATH_LITERAL(".pst"),
    FILE_PATH_LITERAL(".py"),          FILE_PATH_LITERAL(".pyc"),
    FILE_PATH_LITERAL(".pyw"),         FILE_PATH_LITERAL(".rb"),
    FILE_PATH_LITERAL(".reg"),         FILE_PATH_LITERAL(".rpm"),
    FILE_PATH_LITERAL(".scf"),         FILE_PATH_LITERAL(".scr"),
    FILE_PATH_LITERAL(".sct"),         FILE_PATH_LITERAL(".sh"),
    FILE_PATH_LITERAL(".shar"),        FILE_PATH_LITERAL(".shb"),
    FILE_PATH_LITERAL(".shs"),         FILE_PATH_LITERAL(".shtm"),
    FILE_PATH_LITERAL(".shtml"),       FILE_PATH_LITERAL(".spl"),
    FILE_PATH_LITERAL(".svg"),         FILE_PATH_LITERAL(".swf"),
    FILE_PATH_LITERAL(".sys"),         FILE_PATH_LITERAL(".tcsh"),
    FILE_PATH_LITERAL(".url"),         FILE_PATH_LITERAL(".vb"),
    FILE_PATH_LITERAL(".vbe"),         FILE_PATH_LITERAL(".vbs"),
    FILE_PATH_LITERAL(".vsd"),         FILE_PATH_LITERAL(".vsmacros"),
    FILE_PATH_LITERAL(".vss"),         FILE_PATH_LITERAL(".vst"),
    FILE_PATH_LITERAL(".vsw"),         FILE_PATH_LITERAL(".ws"),
    FILE_PATH_LITERAL(".wsc"),         FILE_PATH_LITERAL(".wsf"),
    FILE_PATH_LITERAL(".wsh"),         FILE_PATH_LITERAL(".xbap"),
    FILE_PATH_LITERAL(".xht"),         FILE_PATH_LITERAL(".xhtm"),
    FILE_PATH_LITERAL(".xhtml"),       FILE_PATH_LITERAL(".xml"),
    FILE_PATH_LITERAL(".xsl"),         FILE_PATH_LITERAL(".xslt"),
    FILE_PATH_LITERAL(".website"),     FILE_PATH_LITERAL(".msh1"),
    FILE_PATH_LITERAL(".msh2"),        FILE_PATH_LITERAL(".msh1xml"),
    FILE_PATH_LITERAL(".msh2xml"),     FILE_PATH_LITERAL(".ps1"),
    FILE_PATH_LITERAL(".ps1xml"),      FILE_PATH_LITERAL(".ps2"),
    FILE_PATH_LITERAL(".ps2xml"),      FILE_PATH_LITERAL(".psc1"),
    FILE_PATH_LITERAL(".psc2"),        FILE_PATH_LITERAL(".xnk"),
    FILE_PATH_LITERAL(".appref-ms"),   FILE_PATH_LITERAL(".gadget"),
    FILE_PATH_LITERAL(".efi"),         FILE_PATH_LITERAL(".fon"),
    FILE_PATH_LITERAL(".partial"),     FILE_PATH_LITERAL(".svg"),
    FILE_PATH_LITERAL(".xml"),         FILE_PATH_LITERAL(".xrm_ms"),
    FILE_PATH_LITERAL(".xsl"),         FILE_PATH_LITERAL(".action"),
    FILE_PATH_LITERAL(".bin"),         FILE_PATH_LITERAL(".inx"),
    FILE_PATH_LITERAL(".ipa"),         FILE_PATH_LITERAL(".isu"),
    FILE_PATH_LITERAL(".job"),         FILE_PATH_LITERAL(".out"),
    FILE_PATH_LITERAL(".pad"),         FILE_PATH_LITERAL(".paf"),
    FILE_PATH_LITERAL(".rgs"),         FILE_PATH_LITERAL(".u3p"),
    FILE_PATH_LITERAL(".vbscript"),    FILE_PATH_LITERAL(".workflow"),
    FILE_PATH_LITERAL(".001"),         FILE_PATH_LITERAL(".7z"),
    FILE_PATH_LITERAL(".ace"),         FILE_PATH_LITERAL(".arc"),
    FILE_PATH_LITERAL(".arj"),         FILE_PATH_LITERAL(".b64"),
    FILE_PATH_LITERAL(".balz"),        FILE_PATH_LITERAL(".bhx"),
    FILE_PATH_LITERAL(".bz"),          FILE_PATH_LITERAL(".bz2"),
    FILE_PATH_LITERAL(".bzip2"),       FILE_PATH_LITERAL(".cab"),
    FILE_PATH_LITERAL(".cpio"),        FILE_PATH_LITERAL(".fat"),
    FILE_PATH_LITERAL(".gz"),          FILE_PATH_LITERAL(".gzip"),
    FILE_PATH_LITERAL(".hfs"),         FILE_PATH_LITERAL(".hqx"),
    FILE_PATH_LITERAL(".iso"),         FILE_PATH_LITERAL(".lha"),
    FILE_PATH_LITERAL(".lpaq1"),       FILE_PATH_LITERAL(".lpaq5"),
    FILE_PATH_LITERAL(".lpaq8"),       FILE_PATH_LITERAL(".lzh"),
    FILE_PATH_LITERAL(".lzma"),        FILE_PATH_LITERAL(".mim"),
    FILE_PATH_LITERAL(".ntfs"),        FILE_PATH_LITERAL(".paq8f"),
    FILE_PATH_LITERAL(".paq8jd"),      FILE_PATH_LITERAL(".paq8l"),
    FILE_PATH_LITERAL(".paq8o"),       FILE_PATH_LITERAL(".pea"),
    FILE_PATH_LITERAL(".quad"),        FILE_PATH_LITERAL(".r00"),
    FILE_PATH_LITERAL(".r01"),         FILE_PATH_LITERAL(".r02"),
    FILE_PATH_LITERAL(".r03"),         FILE_PATH_LITERAL(".r04"),
    FILE_PATH_LITERAL(".r05"),         FILE_PATH_LITERAL(".r06"),
    FILE_PATH_LITERAL(".r07"),         FILE_PATH_LITERAL(".r08"),
    FILE_PATH_LITERAL(".r09"),         FILE_PATH_LITERAL(".r10"),
    FILE_PATH_LITERAL(".r11"),         FILE_PATH_LITERAL(".r12"),
    FILE_PATH_LITERAL(".r13"),         FILE_PATH_LITERAL(".r14"),
    FILE_PATH_LITERAL(".r15"),         FILE_PATH_LITERAL(".r16"),
    FILE_PATH_LITERAL(".r17"),         FILE_PATH_LITERAL(".r18"),
    FILE_PATH_LITERAL(".r19"),         FILE_PATH_LITERAL(".r20"),
    FILE_PATH_LITERAL(".r21"),         FILE_PATH_LITERAL(".r22"),
    FILE_PATH_LITERAL(".r23"),         FILE_PATH_LITERAL(".r24"),
    FILE_PATH_LITERAL(".r25"),         FILE_PATH_LITERAL(".r26"),
    FILE_PATH_LITERAL(".r27"),         FILE_PATH_LITERAL(".r28"),
    FILE_PATH_LITERAL(".r29"),         FILE_PATH_LITERAL(".rar"),
    FILE_PATH_LITERAL(".squashfs"),    FILE_PATH_LITERAL(".swm"),
    FILE_PATH_LITERAL(".tar"),         FILE_PATH_LITERAL(".taz"),
    FILE_PATH_LITERAL(".tbz"),         FILE_PATH_LITERAL(".tbz2"),
    FILE_PATH_LITERAL(".tgz"),         FILE_PATH_LITERAL(".tpz"),
    FILE_PATH_LITERAL(".txz"),         FILE_PATH_LITERAL(".tz"),
    FILE_PATH_LITERAL(".udf"),         FILE_PATH_LITERAL(".uu"),
    FILE_PATH_LITERAL(".uue"),         FILE_PATH_LITERAL(".vhd"),
    FILE_PATH_LITERAL(".vmdk"),        FILE_PATH_LITERAL(".wim"),
    FILE_PATH_LITERAL(".wrc"),         FILE_PATH_LITERAL(".xar"),
    FILE_PATH_LITERAL(".xxe"),         FILE_PATH_LITERAL(".xz"),
    FILE_PATH_LITERAL(".z"),           FILE_PATH_LITERAL(".zip"),
    FILE_PATH_LITERAL(".zipx"),        FILE_PATH_LITERAL(".zpaq"),
    FILE_PATH_LITERAL(".cdr"),         FILE_PATH_LITERAL(".dart"),
    FILE_PATH_LITERAL(".dc42"),        FILE_PATH_LITERAL(".diskcopy42"),
    FILE_PATH_LITERAL(".dmg"),         FILE_PATH_LITERAL(".dmgpart"),
    FILE_PATH_LITERAL(".dvdr"),        FILE_PATH_LITERAL(".img"),
    FILE_PATH_LITERAL(".imgpart"),     FILE_PATH_LITERAL(".ndif"),
    FILE_PATH_LITERAL(".smi"),         FILE_PATH_LITERAL(".sparsebundle"),
    FILE_PATH_LITERAL(".sparseimage"), FILE_PATH_LITERAL(".toast"),
    FILE_PATH_LITERAL(".udif"),        FILE_PATH_LITERAL(".run"),        // 262
    FILE_PATH_LITERAL(".mpkg"),        FILE_PATH_LITERAL(".as"),         // 264
    FILE_PATH_LITERAL(".cpgz"),        FILE_PATH_LITERAL(".pax"),        // 266
    FILE_PATH_LITERAL(".xip"),         FILE_PATH_LITERAL(".docx"),       // 268
    FILE_PATH_LITERAL(".docm"),        FILE_PATH_LITERAL(".dott"),       // 270
    FILE_PATH_LITERAL(".dotm"),        FILE_PATH_LITERAL(".docb"),       // 272
    FILE_PATH_LITERAL(".xlsx"),        FILE_PATH_LITERAL(".xlsm"),       // 274
    FILE_PATH_LITERAL(".xltx"),        FILE_PATH_LITERAL(".xltm"),       // 276
    FILE_PATH_LITERAL(".pptx"),        FILE_PATH_LITERAL(".pptm"),       // 278
    FILE_PATH_LITERAL(".potx"),        FILE_PATH_LITERAL(".ppam"),       // 280
    FILE_PATH_LITERAL(".ppsx"),        FILE_PATH_LITERAL(".sldx"),       // 282
    FILE_PATH_LITERAL(".sldm"),        FILE_PATH_LITERAL(".htm"),        // 284
    FILE_PATH_LITERAL(".html"),        FILE_PATH_LITERAL(".xht"),        // 286
    FILE_PATH_LITERAL(".xhtm"),        FILE_PATH_LITERAL(".xhtml"),      // 288
    FILE_PATH_LITERAL(".vdx"),         FILE_PATH_LITERAL(".vsx"),        // 290
    FILE_PATH_LITERAL(".vtx"),         FILE_PATH_LITERAL(".vsdx"),       // 292
    FILE_PATH_LITERAL(".vssx"),        FILE_PATH_LITERAL(".vstx"),       // 294
    FILE_PATH_LITERAL(".vsdm"),        FILE_PATH_LITERAL(".vssm"),       // 296
    FILE_PATH_LITERAL(".vstm"),        FILE_PATH_LITERAL(".btapp"),      // 298
    FILE_PATH_LITERAL(".btskin"),      FILE_PATH_LITERAL(".btinstall"),  // 300
    FILE_PATH_LITERAL(".btkey"),       FILE_PATH_LITERAL(".btsearch"),   // 302
    FILE_PATH_LITERAL(".dhtml"),       FILE_PATH_LITERAL(".dhtm"),       // 304
    FILE_PATH_LITERAL(".dht"),         FILE_PATH_LITERAL(".shtml"),      // 306
    FILE_PATH_LITERAL(".shtm"),        FILE_PATH_LITERAL(".sht"),        // 308
    FILE_PATH_LITERAL(".slk"),                                           // 309
    FILE_PATH_LITERAL(".applescript"), FILE_PATH_LITERAL(".scpt"),       // 311
    FILE_PATH_LITERAL(".scptd"),       FILE_PATH_LITERAL(".seplugin"),   // 313
    FILE_PATH_LITERAL(".osas"),        FILE_PATH_LITERAL(".osax"),       // 315
    FILE_PATH_LITERAL(".settingcontent-ms"), FILE_PATH_LITERAL(".oxt"),  // 317
    // NOTE! When you add a type here, please add the UMA value as a comment.
    // These must all match DownloadItem.DangerousFileType in
    // enums.xml. From 263 onward, they should also match
    // SBClientDownloadExtensions.
};

// The maximum size in KB for the file size metric, file size larger than this
// will be kept in overflow bucket.
const int64_t kMaxFileSizeKb = 4 * 1024 * 1024; /* 4GB. */

const int64_t kHighBandwidthBytesPerSecond = 30 * 1024 * 1024;

// Maps extensions to their matching UMA histogram int value.
int GetDangerousFileType(const base::FilePath& file_path) {
  for (size_t i = 0; i < arraysize(kDangerousFileTypes); ++i) {
    if (file_path.MatchesExtension(kDangerousFileTypes[i]))
      return i + 1;
  }
  return 0;  // Unknown extension.
}

// Helper method to calculate the bandwidth given the data length and time.
int64_t CalculateBandwidthBytesPerSecond(size_t length,
                                         base::TimeDelta elapsed_time) {
  int64_t elapsed_time_ms = elapsed_time.InMilliseconds();
  if (0 == elapsed_time_ms)
    elapsed_time_ms = 1;
  return 1000 * static_cast<int64_t>(length) / elapsed_time_ms;
}

// Helper method to record the bandwidth for a given metric.
void RecordBandwidthMetric(const std::string& metric, int bandwidth) {
  base::UmaHistogramCustomCounts(metric, bandwidth, 1, 50 * 1000 * 1000, 50);
}

// Records a histogram with download source suffix.
std::string CreateHistogramNameWithSuffix(const std::string& name,
                                          DownloadSource download_source) {
  std::string suffix;
  switch (download_source) {
    case DownloadSource::UNKNOWN:
      suffix = "UnknownSource";
      break;
    case DownloadSource::NAVIGATION:
      suffix = "Navigation";
      break;
    case DownloadSource::DRAG_AND_DROP:
      suffix = "DragAndDrop";
      break;
    case DownloadSource::FROM_RENDERER:
      suffix = "FromRenderer";
      break;
    case DownloadSource::EXTENSION_API:
      suffix = "ExtensionAPI";
      break;
    case DownloadSource::EXTENSION_INSTALLER:
      suffix = "ExtensionInstaller";
      break;
    case DownloadSource::INTERNAL_API:
      suffix = "InternalAPI";
      break;
    case DownloadSource::WEB_CONTENTS_API:
      suffix = "WebContentsAPI";
      break;
    case DownloadSource::OFFLINE_PAGE:
      suffix = "OfflinePage";
      break;
    case DownloadSource::CONTEXT_MENU:
      suffix = "ContextMenu";
      break;
  }

  return name + "." + suffix;
}

}  // namespace

void RecordDownloadCount(DownloadCountTypes type) {
  UMA_HISTOGRAM_ENUMERATION("Download.Counts", type,
                            DOWNLOAD_COUNT_TYPES_LAST_ENTRY);
}

void RecordDownloadCountWithSource(DownloadCountTypes type,
                                   DownloadSource download_source) {
  RecordDownloadCount(type);

  std::string name =
      CreateHistogramNameWithSuffix("Download.Counts", download_source);
  base::UmaHistogramEnumeration(name, type, DOWNLOAD_COUNT_TYPES_LAST_ENTRY);
}

void RecordDownloadCompleted(const base::TimeTicks& start,
                             int64_t download_len,
                             bool is_parallelizable,
                             DownloadSource download_source) {
  RecordDownloadCountWithSource(COMPLETED_COUNT, download_source);
  UMA_HISTOGRAM_LONG_TIMES("Download.Time", (base::TimeTicks::Now() - start));
  int64_t max = 1024 * 1024 * 1024;  // One Terabyte.
  download_len /= 1024;              // In Kilobytes
  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.DownloadSize", download_len, 1, max,
                              256);
  if (is_parallelizable) {
    UMA_HISTOGRAM_CUSTOM_COUNTS("Download.DownloadSize.Parallelizable",
                                download_len, 1, max, 256);
  }
}

void RecordDownloadDeletion(base::Time completion_time,
                            const std::string& mime_type) {
  if (completion_time == base::Time())
    return;

  // Records how long the user keeps media files on disk.
  base::TimeDelta retention_time = base::Time::Now() - completion_time;
  int retention_hours = retention_time.InHours();

  DownloadContent type = DownloadContentFromMimeType(mime_type, false);
  if (type == DownloadContent::VIDEO) {
    UMA_HISTOGRAM_CUSTOM_COUNTS("Download.DeleteRetentionTime.Video",
                                retention_hours, 1, kMaxDeletionRetentionHours,
                                50);
  }
  if (type == DownloadContent::AUDIO) {
    UMA_HISTOGRAM_CUSTOM_COUNTS("Download.DeleteRetentionTime.Audio",
                                retention_hours, 1, kMaxDeletionRetentionHours,
                                50);
  }
}

void RecordDownloadInterrupted(DownloadInterruptReason reason,
                               int64_t received,
                               int64_t total,
                               bool is_parallelizable,
                               bool is_parallel_download_enabled,
                               DownloadSource download_source) {
  RecordDownloadCountWithSource(INTERRUPTED_COUNT, download_source);
  if (is_parallelizable) {
    RecordParallelizableDownloadCount(INTERRUPTED_COUNT,
                                      is_parallel_download_enabled);
  }

  std::vector<base::HistogramBase::Sample> samples =
      base::CustomHistogram::ArrayToCustomEnumRanges(kAllInterruptReasonCodes);
  UMA_HISTOGRAM_CUSTOM_ENUMERATION("Download.InterruptedReason", reason,
                                   samples);

  std::string name = CreateHistogramNameWithSuffix("Download.InterruptedReason",
                                                   download_source);
  base::HistogramBase* counter = base::CustomHistogram::FactoryGet(
      name, samples, base::HistogramBase::kUmaTargetedHistogramFlag);
  counter->Add(reason);

  if (is_parallel_download_enabled) {
    UMA_HISTOGRAM_CUSTOM_ENUMERATION(
        "Download.InterruptedReason.ParallelDownload", reason, samples);
  }

  // The maximum should be 2^kBuckets, to have the logarithmic bucket
  // boundaries fall on powers of 2.
  static const int kBuckets = 30;
  static const int64_t kMaxKb = 1 << kBuckets;  // One Terabyte, in Kilobytes.
  int64_t delta_bytes = total - received;
  bool unknown_size = total <= 0;
  int64_t received_kb = received / 1024;
  int64_t total_kb = total / 1024;
  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.InterruptedReceivedSizeK", received_kb,
                              1, kMaxKb, kBuckets);
  if (is_parallel_download_enabled) {
    UMA_HISTOGRAM_CUSTOM_COUNTS(
        "Download.InterruptedReceivedSizeK.ParallelDownload", received_kb, 1,
        kMaxKb, kBuckets);
  }

  if (!unknown_size) {
    UMA_HISTOGRAM_CUSTOM_COUNTS("Download.InterruptedTotalSizeK", total_kb, 1,
                                kMaxKb, kBuckets);
    if (is_parallel_download_enabled) {
      UMA_HISTOGRAM_CUSTOM_COUNTS(
          "Download.InterruptedTotalSizeK.ParallelDownload", total_kb, 1,
          kMaxKb, kBuckets);
    }
    if (delta_bytes == 0) {
      RecordDownloadCountWithSource(INTERRUPTED_AT_END_COUNT, download_source);
      UMA_HISTOGRAM_CUSTOM_ENUMERATION("Download.InterruptedAtEndReason",
                                       reason, samples);

      if (is_parallelizable) {
        RecordParallelizableDownloadCount(INTERRUPTED_AT_END_COUNT,
                                          is_parallel_download_enabled);
        UMA_HISTOGRAM_CUSTOM_ENUMERATION(
            "Download.InterruptedAtEndReason.ParallelDownload", reason,
            samples);
      }
    } else if (delta_bytes > 0) {
      UMA_HISTOGRAM_CUSTOM_COUNTS("Download.InterruptedOverrunBytes",
                                  delta_bytes, 1, kMaxKb, kBuckets);
      if (is_parallel_download_enabled) {
        UMA_HISTOGRAM_CUSTOM_COUNTS(
            "Download.InterruptedOverrunBytes.ParallelDownload", delta_bytes, 1,
            kMaxKb, kBuckets);
      }
    } else {
      UMA_HISTOGRAM_CUSTOM_COUNTS("Download.InterruptedUnderrunBytes",
                                  -delta_bytes, 1, kMaxKb, kBuckets);
      if (is_parallel_download_enabled) {
        UMA_HISTOGRAM_CUSTOM_COUNTS(
            "Download.InterruptedUnderrunBytes.ParallelDownload", -delta_bytes,
            1, kMaxKb, kBuckets);
      }
    }
  }

  UMA_HISTOGRAM_BOOLEAN("Download.InterruptedUnknownSize", unknown_size);
}

void RecordMaliciousDownloadClassified(DownloadDangerType danger_type) {
  UMA_HISTOGRAM_ENUMERATION("Download.MaliciousDownloadClassified", danger_type,
                            DOWNLOAD_DANGER_TYPE_MAX);
}

void RecordDangerousDownloadAccept(DownloadDangerType danger_type,
                                   const base::FilePath& file_path) {
  UMA_HISTOGRAM_ENUMERATION("Download.DangerousDownloadValidated", danger_type,
                            DOWNLOAD_DANGER_TYPE_MAX);
  if (danger_type == DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE) {
    base::UmaHistogramSparse(
        "Download.DangerousFile.DangerousDownloadValidated",
        GetDangerousFileType(file_path));
  }
}

void RecordDangerousDownloadDiscard(DownloadDiscardReason reason,
                                    DownloadDangerType danger_type,
                                    const base::FilePath& file_path) {
  switch (reason) {
    case DOWNLOAD_DISCARD_DUE_TO_USER_ACTION:
      UMA_HISTOGRAM_ENUMERATION("Download.UserDiscard", danger_type,
                                DOWNLOAD_DANGER_TYPE_MAX);
      if (danger_type == DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE) {
        base::UmaHistogramSparse("Download.DangerousFile.UserDiscard",
                                 GetDangerousFileType(file_path));
      }
      break;
    case DOWNLOAD_DISCARD_DUE_TO_SHUTDOWN:
      UMA_HISTOGRAM_ENUMERATION("Download.Discard", danger_type,
                                DOWNLOAD_DANGER_TYPE_MAX);
      if (danger_type == DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE) {
        base::UmaHistogramSparse("Download.DangerousFile.Discard",
                                 GetDangerousFileType(file_path));
      }
      break;
    default:
      NOTREACHED();
  }
}

void RecordAcceptsRanges(const std::string& accepts_ranges,
                         int64_t download_len,
                         bool has_strong_validator) {
  int64_t max = 1024 * 1024 * 1024;  // One Terabyte.
  download_len /= 1024;              // In Kilobytes
  static const int kBuckets = 50;

  if (base::LowerCaseEqualsASCII(accepts_ranges, "none")) {
    UMA_HISTOGRAM_CUSTOM_COUNTS("Download.AcceptRangesNone.KBytes",
                                download_len, 1, max, kBuckets);
  } else if (base::LowerCaseEqualsASCII(accepts_ranges, "bytes")) {
    UMA_HISTOGRAM_CUSTOM_COUNTS("Download.AcceptRangesBytes.KBytes",
                                download_len, 1, max, kBuckets);
    if (has_strong_validator)
      RecordDownloadCount(STRONG_VALIDATOR_AND_ACCEPTS_RANGES);
  } else {
    UMA_HISTOGRAM_CUSTOM_COUNTS("Download.AcceptRangesMissingOrInvalid.KBytes",
                                download_len, 1, max, kBuckets);
  }
}

namespace {

int GetMimeTypeMatch(const std::string& mime_type_string,
                     std::map<std::string, int> mime_type_map) {
  for (const auto& entry : mime_type_map) {
    if (entry.first == mime_type_string) {
      return entry.second;
    }
  }
  return 0;
}

static std::map<std::string, DownloadContent>
getMimeTypeToDownloadContentMap() {
  return {
      {"application/octet-stream", DownloadContent::OCTET_STREAM},
      {"binary/octet-stream", DownloadContent::OCTET_STREAM},
      {"application/pdf", DownloadContent::PDF},
      {"application/msword", DownloadContent::DOCUMENT},
      {"application/"
       "vnd.openxmlformats-officedocument.wordprocessingml.document",
       DownloadContent::DOCUMENT},
      {"application/rtf", DownloadContent::DOCUMENT},
      {"application/vnd.oasis.opendocument.text", DownloadContent::DOCUMENT},
      {"application/vnd.google-apps.document", DownloadContent::DOCUMENT},
      {"application/vnd.ms-excel", DownloadContent::SPREADSHEET},
      {"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
       DownloadContent::SPREADSHEET},
      {"application/vnd.oasis.opendocument.spreadsheet",
       DownloadContent::SPREADSHEET},
      {"application/vnd.google-apps.spreadsheet", DownloadContent::SPREADSHEET},
      {"application/vns.ms-powerpoint", DownloadContent::PRESENTATION},
      {"application/"
       "vnd.openxmlformats-officedocument.presentationml.presentation",
       DownloadContent::PRESENTATION},
      {"application/vnd.oasis.opendocument.presentation",
       DownloadContent::PRESENTATION},
      {"application/vnd.google-apps.presentation",
       DownloadContent::PRESENTATION},
      {"application/zip", DownloadContent::ARCHIVE},
      {"application/x-gzip", DownloadContent::ARCHIVE},
      {"application/x-rar-compressed", DownloadContent::ARCHIVE},
      {"application/x-tar", DownloadContent::ARCHIVE},
      {"application/x-bzip", DownloadContent::ARCHIVE},
      {"application/x-bzip2", DownloadContent::ARCHIVE},
      {"application/x-7z-compressed", DownloadContent::ARCHIVE},
      {"application/x-exe", DownloadContent::EXECUTABLE},
      {"application/java-archive", DownloadContent::EXECUTABLE},
      {"application/vnd.apple.installer+xml", DownloadContent::EXECUTABLE},
      {"application/x-csh", DownloadContent::EXECUTABLE},
      {"application/x-sh", DownloadContent::EXECUTABLE},
      {"application/x-apple-diskimage", DownloadContent::DMG},
      {"application/x-chrome-extension", DownloadContent::CRX},
      {"application/xhtml+xml", DownloadContent::WEB},
      {"application/xml", DownloadContent::WEB},
      {"application/javascript", DownloadContent::WEB},
      {"application/json", DownloadContent::WEB},
      {"application/typescript", DownloadContent::WEB},
      {"application/vnd.mozilla.xul+xml", DownloadContent::WEB},
      {"application/vnd.amazon.ebook", DownloadContent::EBOOK},
      {"application/epub+zip", DownloadContent::EBOOK},
      {"application/vnd.android.package-archive", DownloadContent::APK}};
}

// NOTE: Keep in sync with DownloadImageType in
// tools/metrics/histograms/enums.xml.
enum DownloadImage {
  DOWNLOAD_IMAGE_UNRECOGNIZED = 0,
  DOWNLOAD_IMAGE_GIF = 1,
  DOWNLOAD_IMAGE_JPEG = 2,
  DOWNLOAD_IMAGE_PNG = 3,
  DOWNLOAD_IMAGE_TIFF = 4,
  DOWNLOAD_IMAGE_ICON = 5,
  DOWNLOAD_IMAGE_WEBP = 6,
  DOWNLOAD_IMAGE_PSD = 7,
  DOWNLOAD_IMAGE_SVG = 8,
  DOWNLOAD_IMAGE_MAX = 9,
};

static std::map<std::string, int> getMimeTypeToDownloadImageMap() {
  return {{"image/gif", DOWNLOAD_IMAGE_GIF},
          {"image/jpeg", DOWNLOAD_IMAGE_JPEG},
          {"image/png", DOWNLOAD_IMAGE_PNG},
          {"image/tiff", DOWNLOAD_IMAGE_TIFF},
          {"image/vnd.microsoft.icon", DOWNLOAD_IMAGE_ICON},
          {"image/x-icon", DOWNLOAD_IMAGE_ICON},
          {"image/webp", DOWNLOAD_IMAGE_WEBP},
          {"image/vnd.adobe.photoshop", DOWNLOAD_IMAGE_PSD},
          {"image/svg+xml", DOWNLOAD_IMAGE_SVG}};
}

void RecordDownloadImageType(const std::string& mime_type_string) {
  DownloadImage download_image = DownloadImage(
      GetMimeTypeMatch(mime_type_string, getMimeTypeToDownloadImageMap()));
  UMA_HISTOGRAM_ENUMERATION("Download.ContentType.Image", download_image,
                            DOWNLOAD_IMAGE_MAX);
}

/** Text categories **/

// NOTE: Keep in sync with DownloadTextType in
// tools/metrics/histograms/enums.xml.
enum DownloadText {
  DOWNLOAD_TEXT_UNRECOGNIZED = 0,
  DOWNLOAD_TEXT_PLAIN = 1,
  DOWNLOAD_TEXT_CSS = 2,
  DOWNLOAD_TEXT_CSV = 3,
  DOWNLOAD_TEXT_HTML = 4,
  DOWNLOAD_TEXT_CALENDAR = 5,
  DOWNLOAD_TEXT_MAX = 6,
};

static std::map<std::string, int> getMimeTypeToDownloadTextMap() {
  return {{"text/plain", DOWNLOAD_TEXT_PLAIN},
          {"text/css", DOWNLOAD_TEXT_CSS},
          {"text/csv", DOWNLOAD_TEXT_CSV},
          {"text/html", DOWNLOAD_TEXT_HTML},
          {"text/calendar", DOWNLOAD_TEXT_CALENDAR}};
}

void RecordDownloadTextType(const std::string& mime_type_string) {
  DownloadText download_text = DownloadText(
      GetMimeTypeMatch(mime_type_string, getMimeTypeToDownloadTextMap()));
  UMA_HISTOGRAM_ENUMERATION("Download.ContentType.Text", download_text,
                            DOWNLOAD_TEXT_MAX);
}

/* Audio categories */

// NOTE: Keep in sync with DownloadAudioType in
// tools/metrics/histograms/enums.xml.
enum DownloadAudio {
  DOWNLOAD_AUDIO_UNRECOGNIZED = 0,
  DOWNLOAD_AUDIO_AAC = 1,
  DOWNLOAD_AUDIO_MIDI = 2,
  DOWNLOAD_AUDIO_OGA = 3,
  DOWNLOAD_AUDIO_WAV = 4,
  DOWNLOAD_AUDIO_WEBA = 5,
  DOWNLOAD_AUDIO_3GP = 6,
  DOWNLOAD_AUDIO_3G2 = 7,
  DOWNLOAD_AUDIO_MP3 = 8,
  DOWNLOAD_AUDIO_MAX = 9,
};

static std::map<std::string, int> getMimeTypeToDownloadAudioMap() {
  return {
      {"audio/aac", DOWNLOAD_AUDIO_AAC},   {"audio/midi", DOWNLOAD_AUDIO_MIDI},
      {"audio/ogg", DOWNLOAD_AUDIO_OGA},   {"audio/x-wav", DOWNLOAD_AUDIO_WAV},
      {"audio/webm", DOWNLOAD_AUDIO_WEBA}, {"audio/3gpp", DOWNLOAD_AUDIO_3GP},
      {"audio/3gpp2", DOWNLOAD_AUDIO_3G2}, {"audio/mp3", DOWNLOAD_AUDIO_MP3}};
}

void RecordDownloadAudioType(const std::string& mime_type_string) {
  DownloadAudio download_audio = DownloadAudio(
      GetMimeTypeMatch(mime_type_string, getMimeTypeToDownloadAudioMap()));
  UMA_HISTOGRAM_ENUMERATION("Download.ContentType.Audio", download_audio,
                            DOWNLOAD_AUDIO_MAX);
}

/* Video categories */

// NOTE: Keep in sync with DownloadVideoType in
// tools/metrics/histograms/enums.xml.
enum DownloadVideo {
  DOWNLOAD_VIDEO_UNRECOGNIZED = 0,
  DOWNLOAD_VIDEO_AVI = 1,
  DOWNLOAD_VIDEO_MPEG = 2,
  DOWNLOAD_VIDEO_OGV = 3,
  DOWNLOAD_VIDEO_WEBM = 4,
  DOWNLOAD_VIDEO_3GP = 5,
  DOWNLOAD_VIDEO_3G2 = 6,
  DOWNLOAD_VIDEO_MP4 = 7,
  DOWNLOAD_VIDEO_MOV = 8,
  DOWNLOAD_VIDEO_WMV = 9,
  DOWNLOAD_VIDEO_MAX = 10,
};

static std::map<std::string, int> getMimeTypeToDownloadVideoMap() {
  return {{"video/x-msvideo", DOWNLOAD_VIDEO_AVI},
          {"video/mpeg", DOWNLOAD_VIDEO_MPEG},
          {"video/ogg", DOWNLOAD_VIDEO_OGV},
          {"video/webm", DOWNLOAD_VIDEO_WEBM},
          {"video/3gpp", DOWNLOAD_VIDEO_3GP},
          {"video/3ggp2", DOWNLOAD_VIDEO_3G2},
          {"video/mp4", DOWNLOAD_VIDEO_MP4},
          {"video/quicktime", DOWNLOAD_VIDEO_MOV},
          {"video/x-ms-wmv", DOWNLOAD_VIDEO_WMV}};
}

void RecordDownloadVideoType(const std::string& mime_type_string) {
  DownloadVideo download_video = DownloadVideo(
      GetMimeTypeMatch(mime_type_string, getMimeTypeToDownloadVideoMap()));
  UMA_HISTOGRAM_ENUMERATION("Download.ContentType.Video", download_video,
                            DOWNLOAD_VIDEO_MAX);
}

}  // namespace

DownloadContent DownloadContentFromMimeType(const std::string& mime_type_string,
                                            bool record_content_subcategory) {
  DownloadContent download_content = DownloadContent::UNRECOGNIZED;
  for (const auto& entry : getMimeTypeToDownloadContentMap()) {
    if (entry.first == mime_type_string) {
      download_content = entry.second;
    }
  }

  // Do partial matches.
  if (download_content == DownloadContent::UNRECOGNIZED) {
    if (base::StartsWith(mime_type_string, "text/",
                         base::CompareCase::SENSITIVE)) {
      download_content = DownloadContent::TEXT;
      if (record_content_subcategory)
        RecordDownloadTextType(mime_type_string);
    } else if (base::StartsWith(mime_type_string, "image/",
                                base::CompareCase::SENSITIVE)) {
      download_content = DownloadContent::IMAGE;
      if (record_content_subcategory)
        RecordDownloadImageType(mime_type_string);
    } else if (base::StartsWith(mime_type_string, "audio/",
                                base::CompareCase::SENSITIVE)) {
      download_content = DownloadContent::AUDIO;
      if (record_content_subcategory)
        RecordDownloadAudioType(mime_type_string);
    } else if (base::StartsWith(mime_type_string, "video/",
                                base::CompareCase::SENSITIVE)) {
      download_content = DownloadContent::VIDEO;
      if (record_content_subcategory)
        RecordDownloadVideoType(mime_type_string);
    } else if (base::StartsWith(mime_type_string, "font/",
                                base::CompareCase::SENSITIVE)) {
      download_content = DownloadContent::FONT;
    }
  }

  return download_content;
}

void RecordDownloadMimeType(const std::string& mime_type_string) {
  DownloadContent download_content =
      DownloadContentFromMimeType(mime_type_string, true);
  UMA_HISTOGRAM_ENUMERATION("Download.Start.ContentType", download_content,
                            DownloadContent::MAX);
}

void RecordDownloadMimeTypeForNormalProfile(
    const std::string& mime_type_string) {
  UMA_HISTOGRAM_ENUMERATION(
      "Download.Start.ContentType.NormalProfile",
      DownloadContentFromMimeType(mime_type_string, false),
      DownloadContent::MAX);
}

void RecordDownloadContentDisposition(
    const std::string& content_disposition_string) {
  if (content_disposition_string.empty())
    return;
  net::HttpContentDisposition content_disposition(content_disposition_string,
                                                  std::string());
  int result = content_disposition.parse_result_flags();

  bool is_valid = !content_disposition.filename().empty();
  RecordContentDispositionCount(CONTENT_DISPOSITION_HEADER_PRESENT, true);
  RecordContentDispositionCount(CONTENT_DISPOSITION_IS_VALID, is_valid);
  if (!is_valid)
    return;

  RecordContentDispositionCountFlag(
      CONTENT_DISPOSITION_HAS_DISPOSITION_TYPE, result,
      net::HttpContentDisposition::HAS_DISPOSITION_TYPE);
  RecordContentDispositionCountFlag(
      CONTENT_DISPOSITION_HAS_UNKNOWN_TYPE, result,
      net::HttpContentDisposition::HAS_UNKNOWN_DISPOSITION_TYPE);
  RecordContentDispositionCountFlag(CONTENT_DISPOSITION_HAS_FILENAME, result,
                                    net::HttpContentDisposition::HAS_FILENAME);
  RecordContentDispositionCountFlag(
      CONTENT_DISPOSITION_HAS_EXT_FILENAME, result,
      net::HttpContentDisposition::HAS_EXT_FILENAME);
  RecordContentDispositionCountFlag(
      CONTENT_DISPOSITION_HAS_NON_ASCII_STRINGS, result,
      net::HttpContentDisposition::HAS_NON_ASCII_STRINGS);
  RecordContentDispositionCountFlag(
      CONTENT_DISPOSITION_HAS_PERCENT_ENCODED_STRINGS, result,
      net::HttpContentDisposition::HAS_PERCENT_ENCODED_STRINGS);
  RecordContentDispositionCountFlag(
      CONTENT_DISPOSITION_HAS_RFC2047_ENCODED_STRINGS, result,
      net::HttpContentDisposition::HAS_RFC2047_ENCODED_STRINGS);
}

void RecordFileThreadReceiveBuffers(size_t num_buffers) {
  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.FileThreadReceiveBuffers", num_buffers,
                              1, 100, 100);
}

void RecordOpen(const base::Time& end, bool first) {
  if (!end.is_null()) {
    UMA_HISTOGRAM_LONG_TIMES("Download.OpenTime", (base::Time::Now() - end));
    if (first) {
      UMA_HISTOGRAM_LONG_TIMES("Download.FirstOpenTime",
                               (base::Time::Now() - end));
    }
  }
}

void RecordOpensOutstanding(int size) {
  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.OpensOutstanding", size, 1 /*min*/,
                              (1 << 10) /*max*/, 64 /*num_buckets*/);
}

void RecordContiguousWriteTime(base::TimeDelta time_blocked) {
  UMA_HISTOGRAM_TIMES("Download.FileThreadBlockedTime", time_blocked);
}

// Record what percentage of the time we have the network flow controlled.
void RecordNetworkBlockage(base::TimeDelta resource_handler_lifetime,
                           base::TimeDelta resource_handler_blocked_time) {
  int percentage = 0;
  // Avoid division by zero errors.
  if (!resource_handler_blocked_time.is_zero()) {
    percentage =
        resource_handler_blocked_time * 100 / resource_handler_lifetime;
  }

  UMA_HISTOGRAM_COUNTS_100("Download.ResourceHandlerBlockedPercentage",
                           percentage);
}

void RecordFileBandwidth(size_t length,
                         base::TimeDelta disk_write_time,
                         base::TimeDelta elapsed_time) {
  RecordBandwidthMetric("Download.BandwidthOverallBytesPerSecond",
                        CalculateBandwidthBytesPerSecond(length, elapsed_time));
  RecordBandwidthMetric(
      "Download.BandwidthDiskBytesPerSecond",
      CalculateBandwidthBytesPerSecond(length, disk_write_time));
}

void RecordParallelizableDownloadCount(DownloadCountTypes type,
                                       bool is_parallel_download_enabled) {
  std::string histogram_name = is_parallel_download_enabled
                                   ? "Download.Counts.ParallelDownload"
                                   : "Download.Counts.ParallelizableDownload";
  base::UmaHistogramEnumeration(histogram_name, type,
                                DOWNLOAD_COUNT_TYPES_LAST_ENTRY);
}

void RecordParallelDownloadRequestCount(int request_count) {
  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.ParallelDownloadRequestCount",
                              request_count, 1, 10, 11);
}

void RecordParallelDownloadAddStreamSuccess(bool success) {
  UMA_HISTOGRAM_BOOLEAN("Download.ParallelDownloadAddStreamSuccess", success);
}

void RecordParallelizableContentLength(int64_t content_length) {
  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.ContentLength.Parallelizable",
                              content_length / 1024, 1, kMaxFileSizeKb, 50);
}

void RecordParallelizableDownloadStats(
    size_t bytes_downloaded_with_parallel_streams,
    base::TimeDelta time_with_parallel_streams,
    size_t bytes_downloaded_without_parallel_streams,
    base::TimeDelta time_without_parallel_streams,
    bool uses_parallel_requests) {
  RecordParallelizableDownloadAverageStats(
      bytes_downloaded_with_parallel_streams +
          bytes_downloaded_without_parallel_streams,
      time_with_parallel_streams + time_without_parallel_streams);

  int64_t bandwidth_without_parallel_streams = 0;
  if (bytes_downloaded_without_parallel_streams > 0) {
    bandwidth_without_parallel_streams = CalculateBandwidthBytesPerSecond(
        bytes_downloaded_without_parallel_streams,
        time_without_parallel_streams);
    if (uses_parallel_requests) {
      RecordBandwidthMetric(
          "Download.ParallelizableDownloadBandwidth."
          "WithParallelRequestsSingleStream",
          bandwidth_without_parallel_streams);
    } else {
      RecordBandwidthMetric(
          "Download.ParallelizableDownloadBandwidth."
          "WithoutParallelRequests",
          bandwidth_without_parallel_streams);
    }
  }

  if (!uses_parallel_requests)
    return;

  base::TimeDelta time_saved;
  if (bytes_downloaded_with_parallel_streams > 0) {
    int64_t bandwidth_with_parallel_streams = CalculateBandwidthBytesPerSecond(
        bytes_downloaded_with_parallel_streams, time_with_parallel_streams);
    RecordBandwidthMetric(
        "Download.ParallelizableDownloadBandwidth."
        "WithParallelRequestsMultipleStreams",
        bandwidth_with_parallel_streams);
    if (bandwidth_without_parallel_streams > 0) {
      time_saved = base::TimeDelta::FromMilliseconds(
                       1000.0 * bytes_downloaded_with_parallel_streams /
                       bandwidth_without_parallel_streams) -
                   time_with_parallel_streams;
      int bandwidth_ratio_percentage =
          (100.0 * bandwidth_with_parallel_streams) /
          bandwidth_without_parallel_streams;
      UMA_HISTOGRAM_CUSTOM_COUNTS(
          "Download.ParallelDownload.BandwidthRatioPercentage",
          bandwidth_ratio_percentage, 0, 400, 101);
      base::TimeDelta total_time =
          time_with_parallel_streams + time_without_parallel_streams;
      size_t total_size = bytes_downloaded_with_parallel_streams +
                          bytes_downloaded_without_parallel_streams;
      base::TimeDelta non_parallel_time = base::TimeDelta::FromSecondsD(
          static_cast<double>(total_size) / bandwidth_without_parallel_streams);
      int time_ratio_percentage =
          100.0 * total_time.InSecondsF() / non_parallel_time.InSecondsF();
      UMA_HISTOGRAM_CUSTOM_COUNTS(
          "Download.ParallelDownload.TotalTimeRatioPercentage",
          time_ratio_percentage, 0, 200, 101);
    }
  }

  int kMillisecondsPerHour =
      base::checked_cast<int>(base::Time::kMillisecondsPerSecond * 60 * 60);
  if (time_saved >= base::TimeDelta()) {
    UMA_HISTOGRAM_CUSTOM_COUNTS(
        "Download.EstimatedTimeSavedWithParallelDownload",
        time_saved.InMilliseconds(), 0, kMillisecondsPerHour, 50);
  } else {
    UMA_HISTOGRAM_CUSTOM_COUNTS(
        "Download.EstimatedTimeWastedWithParallelDownload",
        -time_saved.InMilliseconds(), 0, kMillisecondsPerHour, 50);
  }
}

void RecordParallelizableDownloadAverageStats(
    int64_t bytes_downloaded,
    const base::TimeDelta& time_span) {
  if (time_span.is_zero() || bytes_downloaded <= 0)
    return;

  int64_t average_bandwidth =
      CalculateBandwidthBytesPerSecond(bytes_downloaded, time_span);
  int64_t file_size_kb = bytes_downloaded / 1024;
  RecordBandwidthMetric("Download.ParallelizableDownloadBandwidth",
                        average_bandwidth);
  UMA_HISTOGRAM_LONG_TIMES("Download.Parallelizable.DownloadTime", time_span);
  UMA_HISTOGRAM_CUSTOM_COUNTS("Download.Parallelizable.FileSize", file_size_kb,
                              1, kMaxFileSizeKb, 50);
  if (average_bandwidth > kHighBandwidthBytesPerSecond) {
    UMA_HISTOGRAM_LONG_TIMES(
        "Download.Parallelizable.DownloadTime.HighDownloadBandwidth",
        time_span);
    UMA_HISTOGRAM_CUSTOM_COUNTS(
        "Download.Parallelizable.FileSize.HighDownloadBandwidth", file_size_kb,
        1, kMaxFileSizeKb, 50);
  }
}

void RecordParallelDownloadCreationEvent(ParallelDownloadCreationEvent event) {
  UMA_HISTOGRAM_ENUMERATION("Download.ParallelDownload.CreationEvent", event,
                            ParallelDownloadCreationEvent::COUNT);
}

void RecordDownloadFileRenameResultAfterRetry(
    base::TimeDelta time_since_first_failure,
    DownloadInterruptReason interrupt_reason) {
  if (interrupt_reason == DOWNLOAD_INTERRUPT_REASON_NONE) {
    UMA_HISTOGRAM_TIMES("Download.TimeToRenameSuccessAfterInitialFailure",
                        time_since_first_failure);
  } else {
    UMA_HISTOGRAM_TIMES("Download.TimeToRenameFailureAfterInitialFailure",
                        time_since_first_failure);
  }
}

void RecordSavePackageEvent(SavePackageEvent event) {
  UMA_HISTOGRAM_ENUMERATION("Download.SavePackage", event,
                            SAVE_PACKAGE_LAST_ENTRY);
}

void RecordOriginStateOnResumption(bool is_partial,
                                   OriginStateOnResumption state) {
  if (is_partial)
    UMA_HISTOGRAM_ENUMERATION("Download.OriginStateOnPartialResumption", state,
                              ORIGIN_STATE_ON_RESUMPTION_MAX);
  else
    UMA_HISTOGRAM_ENUMERATION("Download.OriginStateOnFullResumption", state,
                              ORIGIN_STATE_ON_RESUMPTION_MAX);
}

namespace {

// Enumeration for histogramming purposes.
// These values are written to logs.  New enum values can be added, but existing
// enums must never be renumbered or deleted and reused.
enum DownloadConnectionSecurity {
  DOWNLOAD_SECURE = 0,  // Final download url and its redirects all use https
  DOWNLOAD_TARGET_INSECURE =
      1,  // Final download url uses http, redirects are all
          // https
  DOWNLOAD_REDIRECT_INSECURE =
      2,  // Final download url uses https, but at least
          // one redirect uses http
  DOWNLOAD_REDIRECT_TARGET_INSECURE =
      3,                      // Final download url uses http, and at
                              // least one redirect uses http
  DOWNLOAD_TARGET_OTHER = 4,  // Final download url uses a scheme not present in
                              // this enumeration
  DOWNLOAD_TARGET_BLOB = 5,   // Final download url uses blob scheme
  DOWNLOAD_TARGET_DATA = 6,   //  Final download url uses data scheme
  DOWNLOAD_TARGET_FILE = 7,   //  Final download url uses file scheme
  DOWNLOAD_TARGET_FILESYSTEM = 8,  //  Final download url uses filesystem scheme
  DOWNLOAD_TARGET_FTP = 9,         // Final download url uses ftp scheme
  DOWNLOAD_CONNECTION_SECURITY_MAX
};

}  // namespace

void RecordDownloadConnectionSecurity(const GURL& download_url,
                                      const std::vector<GURL>& url_chain) {
  DownloadConnectionSecurity state = DOWNLOAD_TARGET_OTHER;
  if (download_url.SchemeIsHTTPOrHTTPS()) {
    bool is_final_download_secure = download_url.SchemeIsCryptographic();
    bool is_redirect_chain_secure = true;
    if (url_chain.size() > std::size_t(1)) {
      for (std::size_t i = std::size_t(0); i < url_chain.size() - 1; i++) {
        if (!url_chain[i].SchemeIsCryptographic()) {
          is_redirect_chain_secure = false;
          break;
        }
      }
    }
    state = is_final_download_secure
                ? is_redirect_chain_secure ? DOWNLOAD_SECURE
                                           : DOWNLOAD_REDIRECT_INSECURE
                : is_redirect_chain_secure ? DOWNLOAD_TARGET_INSECURE
                                           : DOWNLOAD_REDIRECT_TARGET_INSECURE;
  } else if (download_url.SchemeIsBlob()) {
    state = DOWNLOAD_TARGET_BLOB;
  } else if (download_url.SchemeIs(url::kDataScheme)) {
    state = DOWNLOAD_TARGET_DATA;
  } else if (download_url.SchemeIsFile()) {
    state = DOWNLOAD_TARGET_FILE;
  } else if (download_url.SchemeIsFileSystem()) {
    state = DOWNLOAD_TARGET_FILESYSTEM;
  } else if (download_url.SchemeIs(url::kFtpScheme)) {
    state = DOWNLOAD_TARGET_FTP;
  }

  UMA_HISTOGRAM_ENUMERATION("Download.TargetConnectionSecurity", state,
                            DOWNLOAD_CONNECTION_SECURITY_MAX);
}

void RecordDownloadContentTypeSecurity(
    const GURL& download_url,
    const std::vector<GURL>& url_chain,
    const std::string& mime_type,
    const base::RepeatingCallback<bool(const GURL&)>&
        is_origin_secure_callback) {
  bool is_final_download_secure = is_origin_secure_callback.Run(download_url);
  bool is_redirect_chain_secure = true;
  for (const auto& url : url_chain) {
    if (!is_origin_secure_callback.Run(url)) {
      is_redirect_chain_secure = false;
      break;
    }
  }

  DownloadContent download_content =
      download::DownloadContentFromMimeType(mime_type, false);
  if (is_final_download_secure && is_redirect_chain_secure) {
    UMA_HISTOGRAM_ENUMERATION("Download.Start.ContentType.SecureChain",
                              download_content, DownloadContent::MAX);
  } else {
    UMA_HISTOGRAM_ENUMERATION("Download.Start.ContentType.InsecureChain",
                              download_content, DownloadContent::MAX);
  }
}

void RecordDownloadSourcePageTransitionType(
    const base::Optional<ui::PageTransition>& page_transition) {
  if (!page_transition)
    return;

  UMA_HISTOGRAM_ENUMERATION(
      "Download.PageTransition",
      ui::PageTransitionStripQualifier(page_transition.value()),
      ui::PAGE_TRANSITION_LAST_CORE + 1);
}

void RecordDownloadHttpResponseCode(int response_code) {
  UMA_HISTOGRAM_CUSTOM_ENUMERATION(
      "Download.HttpResponseCode",
      net::HttpUtil::MapStatusCodeForHistogram(response_code),
      net::HttpUtil::GetStatusCodesForHistogram());
}

}  // namespace download