src/chrome/browser/extensions/updater/extension_updater.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/extensions/updater/extension_updater.h"
   6
   7 #include <algorithm>
   8 #include <set>
   9 #include <vector>
  10
  11 #include "base/bind.h"
  12 #include "base/logging.h"
  13 #include "base/metrics/histogram.h"
  14 #include "base/prefs/pref_service.h"
  15 #include "base/rand_util.h"
  16 #include "base/stl_util.h"
  17 #include "base/strings/string_number_conversions.h"
  18 #include "base/strings/string_split.h"
  19 #include "chrome/browser/chrome_notification_types.h"
  20 #include "chrome/browser/extensions/api/module/module.h"
  21 #include "chrome/browser/extensions/crx_installer.h"
  22 #include "chrome/browser/extensions/extension_service.h"
  23 #include "chrome/browser/extensions/updater/extension_downloader.h"
  24 #include "chrome/browser/profiles/profile.h"
  25 #include "chrome/common/pref_names.h"
  26 #include "content/public/browser/browser_thread.h"
  27 #include "content/public/browser/notification_details.h"
  28 #include "content/public/browser/notification_service.h"
  29 #include "content/public/browser/notification_source.h"
  30 #include "crypto/sha2.h"
  31 #include "extensions/browser/pending_extension_manager.h"
  32 #include "extensions/browser/pref_names.h"
  33 #include "extensions/common/constants.h"
  34 #include "extensions/common/extension.h"
  35 #include "extensions/common/extension_set.h"
  36 #include "extensions/common/manifest.h"
  37
  38 using base::RandDouble;
  39 using base::RandInt;
  40 using base::Time;
  41 using base::TimeDelta;
  42 using content::BrowserThread;
  43
  44 typedef extensions::ExtensionDownloaderDelegate::Error Error;
  45 typedef extensions::ExtensionDownloaderDelegate::PingResult PingResult;
  46
  47 namespace {
  48
  49 // Wait at least 5 minutes after browser startup before we do any checks. If you
  50 // change this value, make sure to update comments where it is used.
  51 const int kStartupWaitSeconds = 60 * 5;
  52
  53 // For sanity checking on update frequency - enforced in release mode only.
  54 #ifdef NDEBUG
  55 const int kMinUpdateFrequencySeconds = 30;
  56 #endif
  57 const int kMaxUpdateFrequencySeconds = 60 * 60 * 24 * 7;  // 7 days
  58
  59 // Require at least 5 seconds between consecutive non-succesful extension update
  60 // checks.
  61 const int kMinUpdateThrottleTime = 5;
  62
  63 // When we've computed a days value, we want to make sure we don't send a
  64 // negative value (due to the system clock being set backwards, etc.), since -1
  65 // is a special sentinel value that means "never pinged", and other negative
  66 // values don't make sense.
  67 int SanitizeDays(int days) {
  68   if (days < 0)
  69     return 0;
  70   return days;
  71 }
  72
  73 // Calculates the value to use for the ping days parameter.
  74 int CalculatePingDays(const Time& last_ping_day) {
  75   int days = extensions::ManifestFetchData::kNeverPinged;
  76   if (!last_ping_day.is_null()) {
  77     days = SanitizeDays((Time::Now() - last_ping_day).InDays());
  78   }
  79   return days;
  80 }
  81
  82 int CalculateActivePingDays(const Time& last_active_ping_day,
  83                             bool hasActiveBit) {
  84   if (!hasActiveBit)
  85     return 0;
  86   if (last_active_ping_day.is_null())
  87     return extensions::ManifestFetchData::kNeverPinged;
  88   return SanitizeDays((Time::Now() - last_active_ping_day).InDays());
  89 }
  90
  91 }  // namespace
  92
  93 namespace extensions {
  94
  95 ExtensionUpdater::CheckParams::CheckParams()
  96     : install_immediately(false) {}
  97
  98 ExtensionUpdater::CheckParams::~CheckParams() {}
  99
 100 ExtensionUpdater::FetchedCRXFile::FetchedCRXFile(
 101     const std::string& i,
 102     const base::FilePath& p,
 103     bool file_ownership_passed,
 104     const GURL& u,
 105     const std::set<int>& request_ids)
 106     : extension_id(i),
 107       path(p),
 108       file_ownership_passed(file_ownership_passed),
 109       download_url(u),
 110       request_ids(request_ids) {}
 111
 112 ExtensionUpdater::FetchedCRXFile::FetchedCRXFile()
 113     : path(), file_ownership_passed(true), download_url() {}
 114
 115 ExtensionUpdater::FetchedCRXFile::~FetchedCRXFile() {}
 116
 117 ExtensionUpdater::InProgressCheck::InProgressCheck()
 118     : install_immediately(false) {}
 119
 120 ExtensionUpdater::InProgressCheck::~InProgressCheck() {}
 121
 122 struct ExtensionUpdater::ThrottleInfo {
 123   ThrottleInfo()
 124       : in_progress(true),
 125         throttle_delay(kMinUpdateThrottleTime),
 126         check_start(Time::Now()) {}
 127
 128   bool in_progress;
 129   int throttle_delay;
 130   Time check_start;
 131 };
 132
 133 ExtensionUpdater::ExtensionUpdater(ExtensionServiceInterface* service,
 134                                    ExtensionPrefs* extension_prefs,
 135                                    PrefService* prefs,
 136                                    Profile* profile,
 137                                    int frequency_seconds,
 138                                    ExtensionCache* cache)
 139     : alive_(false),
 140       weak_ptr_factory_(this),
 141       service_(service), frequency_seconds_(frequency_seconds),
 142       will_check_soon_(false), extension_prefs_(extension_prefs),
 143       prefs_(prefs), profile_(profile),
 144       next_request_id_(0),
 145       crx_install_is_running_(false),
 146       extension_cache_(cache) {
 147   DCHECK_GE(frequency_seconds_, 5);
 148   DCHECK_LE(frequency_seconds_, kMaxUpdateFrequencySeconds);
 149 #ifdef NDEBUG
 150   // In Release mode we enforce that update checks don't happen too often.
 151   frequency_seconds_ = std::max(frequency_seconds_, kMinUpdateFrequencySeconds);
 152 #endif
 153   frequency_seconds_ = std::min(frequency_seconds_, kMaxUpdateFrequencySeconds);
 154
 155   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_INSTALLED,
 156                  content::NotificationService::AllBrowserContextsAndSources());
 157 }
 158
 159 ExtensionUpdater::~ExtensionUpdater() {
 160   Stop();
 161 }
 162
 163 // The overall goal here is to balance keeping clients up to date while
 164 // avoiding a thundering herd against update servers.
 165 TimeDelta ExtensionUpdater::DetermineFirstCheckDelay() {
 166   DCHECK(alive_);
 167   // If someone's testing with a quick frequency, just allow it.
 168   if (frequency_seconds_ < kStartupWaitSeconds)
 169     return TimeDelta::FromSeconds(frequency_seconds_);
 170
 171   // If we've never scheduled a check before, start at frequency_seconds_.
 172   if (!prefs_->HasPrefPath(pref_names::kNextUpdateCheck))
 173     return TimeDelta::FromSeconds(frequency_seconds_);
 174
 175   // If it's been a long time since our last actual check, we want to do one
 176   // relatively soon.
 177   Time now = Time::Now();
 178   Time last = Time::FromInternalValue(prefs_->GetInt64(
 179       pref_names::kLastUpdateCheck));
 180   int days = (now - last).InDays();
 181   if (days >= 30) {
 182     // Wait 5-10 minutes.
 183     return TimeDelta::FromSeconds(RandInt(kStartupWaitSeconds,
 184                                           kStartupWaitSeconds * 2));
 185   } else if (days >= 14) {
 186     // Wait 10-20 minutes.
 187     return TimeDelta::FromSeconds(RandInt(kStartupWaitSeconds * 2,
 188                                           kStartupWaitSeconds * 4));
 189   } else if (days >= 3) {
 190     // Wait 20-40 minutes.
 191     return TimeDelta::FromSeconds(RandInt(kStartupWaitSeconds * 4,
 192                                           kStartupWaitSeconds * 8));
 193   }
 194
 195   // Read the persisted next check time, and use that if it isn't too soon.
 196   // Otherwise pick something random.
 197   Time saved_next = Time::FromInternalValue(prefs_->GetInt64(
 198       pref_names::kNextUpdateCheck));
 199   Time earliest = now + TimeDelta::FromSeconds(kStartupWaitSeconds);
 200   if (saved_next >= earliest) {
 201     return saved_next - now;
 202   } else {
 203     return TimeDelta::FromSeconds(RandInt(kStartupWaitSeconds,
 204                                           frequency_seconds_));
 205   }
 206 }
 207
 208 void ExtensionUpdater::Start() {
 209   DCHECK(!alive_);
 210   // If these are NULL, then that means we've been called after Stop()
 211   // has been called.
 212   DCHECK(service_);
 213   DCHECK(extension_prefs_);
 214   DCHECK(prefs_);
 215   DCHECK(profile_);
 216   DCHECK(!weak_ptr_factory_.HasWeakPtrs());
 217   alive_ = true;
 218   // Make sure our prefs are registered, then schedule the first check.
 219   ScheduleNextCheck(DetermineFirstCheckDelay());
 220 }
 221
 222 void ExtensionUpdater::Stop() {
 223   weak_ptr_factory_.InvalidateWeakPtrs();
 224   alive_ = false;
 225   service_ = NULL;
 226   extension_prefs_ = NULL;
 227   prefs_ = NULL;
 228   profile_ = NULL;
 229   timer_.Stop();
 230   will_check_soon_ = false;
 231   downloader_.reset();
 232 }
 233
 234 void ExtensionUpdater::ScheduleNextCheck(const TimeDelta& target_delay) {
 235   DCHECK(alive_);
 236   DCHECK(!timer_.IsRunning());
 237   DCHECK(target_delay >= TimeDelta::FromSeconds(1));
 238
 239   // Add +/- 10% random jitter.
 240   double delay_ms = target_delay.InMillisecondsF();
 241   double jitter_factor = (RandDouble() * .2) - 0.1;
 242   delay_ms += delay_ms * jitter_factor;
 243   TimeDelta actual_delay = TimeDelta::FromMilliseconds(
 244       static_cast<int64>(delay_ms));
 245
 246   // Save the time of next check.
 247   Time next = Time::Now() + actual_delay;
 248   prefs_->SetInt64(pref_names::kNextUpdateCheck, next.ToInternalValue());
 249
 250   timer_.Start(FROM_HERE, actual_delay, this, &ExtensionUpdater::TimerFired);
 251 }
 252
 253 void ExtensionUpdater::TimerFired() {
 254   DCHECK(alive_);
 255   CheckNow(default_params_);
 256
 257   // If the user has overridden the update frequency, don't bother reporting
 258   // this.
 259   if (frequency_seconds_ == extensions::kDefaultUpdateFrequencySeconds) {
 260     Time last = Time::FromInternalValue(prefs_->GetInt64(
 261         pref_names::kLastUpdateCheck));
 262     if (last.ToInternalValue() != 0) {
 263       // Use counts rather than time so we can use minutes rather than millis.
 264       UMA_HISTOGRAM_CUSTOM_COUNTS("Extensions.UpdateCheckGap",
 265           (Time::Now() - last).InMinutes(),
 266           TimeDelta::FromSeconds(kStartupWaitSeconds).InMinutes(),
 267           TimeDelta::FromDays(40).InMinutes(),
 268           50);  // 50 buckets seems to be the default.
 269     }
 270   }
 271
 272   // Save the last check time, and schedule the next check.
 273   int64 now = Time::Now().ToInternalValue();
 274   prefs_->SetInt64(pref_names::kLastUpdateCheck, now);
 275   ScheduleNextCheck(TimeDelta::FromSeconds(frequency_seconds_));
 276 }
 277
 278 void ExtensionUpdater::CheckSoon() {
 279   DCHECK(alive_);
 280   if (will_check_soon_)
 281     return;
 282   if (BrowserThread::PostTask(
 283           BrowserThread::UI, FROM_HERE,
 284           base::Bind(&ExtensionUpdater::DoCheckSoon,
 285                      weak_ptr_factory_.GetWeakPtr()))) {
 286     will_check_soon_ = true;
 287   } else {
 288     NOTREACHED();
 289   }
 290 }
 291
 292 bool ExtensionUpdater::WillCheckSoon() const {
 293   return will_check_soon_;
 294 }
 295
 296 void ExtensionUpdater::DoCheckSoon() {
 297   DCHECK(will_check_soon_);
 298   CheckNow(default_params_);
 299   will_check_soon_ = false;
 300 }
 301
 302 void ExtensionUpdater::AddToDownloader(
 303     const ExtensionSet* extensions,
 304     const std::list<std::string>& pending_ids,
 305     int request_id) {
 306   InProgressCheck& request = requests_in_progress_[request_id];
 307   for (ExtensionSet::const_iterator extension_iter = extensions->begin();
 308        extension_iter != extensions->end(); ++extension_iter) {
 309     const Extension& extension = *extension_iter->get();
 310     if (!Manifest::IsAutoUpdateableLocation(extension.location())) {
 311       VLOG(2) << "Extension " << extension.id() << " is not auto updateable";
 312       continue;
 313     }
 314     // An extension might be overwritten by policy, and have its update url
 315     // changed. Make sure existing extensions aren't fetched again, if a
 316     // pending fetch for an extension with the same id already exists.
 317     std::list<std::string>::const_iterator pending_id_iter = std::find(
 318         pending_ids.begin(), pending_ids.end(), extension.id());
 319     if (pending_id_iter == pending_ids.end()) {
 320       if (downloader_->AddExtension(extension, request_id))
 321         request.in_progress_ids_.push_back(extension.id());
 322     }
 323   }
 324 }
 325
 326 void ExtensionUpdater::CheckNow(const CheckParams& params) {
 327   int request_id = next_request_id_++;
 328
 329   VLOG(2) << "Starting update check " << request_id;
 330   if (params.ids.empty())
 331     NotifyStarted();
 332
 333   DCHECK(alive_);
 334
 335   InProgressCheck& request = requests_in_progress_[request_id];
 336   request.callback = params.callback;
 337   request.install_immediately = params.install_immediately;
 338
 339   if (!downloader_.get()) {
 340     downloader_.reset(
 341         new ExtensionDownloader(this, profile_->GetRequestContext()));
 342   }
 343
 344   // Add fetch records for extensions that should be fetched by an update URL.
 345   // These extensions are not yet installed. They come from group policy
 346   // and external install sources.
 347   const PendingExtensionManager* pending_extension_manager =
 348       service_->pending_extension_manager();
 349
 350   std::list<std::string> pending_ids;
 351
 352   if (params.ids.empty()) {
 353     // If no extension ids are specified, check for updates for all extensions.
 354     pending_extension_manager->GetPendingIdsForUpdateCheck(&pending_ids);
 355
 356     std::list<std::string>::const_iterator iter;
 357     for (iter = pending_ids.begin(); iter != pending_ids.end(); ++iter) {
 358       const PendingExtensionInfo* info = pending_extension_manager->GetById(
 359           *iter);
 360       if (!Manifest::IsAutoUpdateableLocation(info->install_source())) {
 361         VLOG(2) << "Extension " << *iter << " is not auto updateable";
 362         continue;
 363       }
 364       if (downloader_->AddPendingExtension(*iter, info->update_url(),
 365                                            request_id))
 366         request.in_progress_ids_.push_back(*iter);
 367     }
 368
 369     AddToDownloader(service_->extensions(), pending_ids, request_id);
 370     AddToDownloader(service_->disabled_extensions(), pending_ids, request_id);
 371   } else {
 372     for (std::list<std::string>::const_iterator it = params.ids.begin();
 373          it != params.ids.end(); ++it) {
 374       const Extension* extension = service_->GetExtensionById(*it, true);
 375       DCHECK(extension);
 376       if (downloader_->AddExtension(*extension, request_id))
 377         request.in_progress_ids_.push_back(extension->id());
 378     }
 379   }
 380
 381   // StartAllPending() might call OnExtensionDownloadFailed/Finished before
 382   // it returns, which would cause NotifyIfFinished to incorrectly try to
 383   // send out a notification. So check before we call StartAllPending if any
 384   // extensions are going to be updated, and use that to figure out if
 385   // NotifyIfFinished should be called.
 386   bool noChecks = request.in_progress_ids_.empty();
 387
 388   // StartAllPending() will call OnExtensionDownloadFailed or
 389   // OnExtensionDownloadFinished for each extension that was checked.
 390   downloader_->StartAllPending(extension_cache_);
 391
 392   if (noChecks)
 393     NotifyIfFinished(request_id);
 394 }
 395
 396 bool ExtensionUpdater::CheckExtensionSoon(const std::string& extension_id,
 397                                           const FinishedCallback& callback) {
 398   bool have_throttle_info = ContainsKey(throttle_info_, extension_id);
 399   ThrottleInfo& info = throttle_info_[extension_id];
 400   if (have_throttle_info) {
 401     // We already had a ThrottleInfo object for this extension, check if the
 402     // update check request should be allowed.
 403
 404     // If another check is in progress, don't start a new check.
 405     if (info.in_progress)
 406       return false;
 407
 408     Time now = Time::Now();
 409     Time last = info.check_start;
 410     // If somehow time moved back, we don't want to infinitely keep throttling.
 411     if (now < last) {
 412       last = now;
 413       info.check_start = now;
 414     }
 415     Time earliest = last + TimeDelta::FromSeconds(info.throttle_delay);
 416     // If check is too soon, throttle.
 417     if (now < earliest)
 418       return false;
 419
 420     // TODO(mek): Somehow increase time between allowing checks when checks
 421     // are repeatedly throttled and don't result in updates being installed.
 422
 423     // It's okay to start a check, update values.
 424     info.check_start = now;
 425     info.in_progress = true;
 426   }
 427
 428   CheckParams params;
 429   params.ids.push_back(extension_id);
 430   params.callback = base::Bind(&ExtensionUpdater::ExtensionCheckFinished,
 431                                weak_ptr_factory_.GetWeakPtr(),
 432                                extension_id, callback);
 433   CheckNow(params);
 434   return true;
 435 }
 436
 437 void ExtensionUpdater::ExtensionCheckFinished(
 438     const std::string& extension_id,
 439     const FinishedCallback& callback) {
 440   std::map<std::string, ThrottleInfo>::iterator it =
 441       throttle_info_.find(extension_id);
 442   if (it != throttle_info_.end()) {
 443     it->second.in_progress = false;
 444   }
 445   callback.Run();
 446 }
 447
 448 void ExtensionUpdater::OnExtensionDownloadFailed(
 449     const std::string& id,
 450     Error error,
 451     const PingResult& ping,
 452     const std::set<int>& request_ids) {
 453   DCHECK(alive_);
 454   UpdatePingData(id, ping);
 455   bool install_immediately = false;
 456   for (std::set<int>::const_iterator it = request_ids.begin();
 457        it != request_ids.end(); ++it) {
 458     InProgressCheck& request = requests_in_progress_[*it];
 459     install_immediately |= request.install_immediately;
 460     request.in_progress_ids_.remove(id);
 461     NotifyIfFinished(*it);
 462   }
 463
 464   // This method is called if no updates were found. However a previous update
 465   // check might have queued an update for this extension already. If a
 466   // current update check has |install_immediately| set the previously
 467   // queued update should be installed now.
 468   if (install_immediately && service_->GetPendingExtensionUpdate(id))
 469     service_->FinishDelayedInstallation(id);
 470 }
 471
 472 void ExtensionUpdater::OnExtensionDownloadFinished(
 473     const std::string& id,
 474     const base::FilePath& path,
 475     bool file_ownership_passed,
 476     const GURL& download_url,
 477     const std::string& version,
 478     const PingResult& ping,
 479     const std::set<int>& request_ids) {
 480   DCHECK(alive_);
 481   UpdatePingData(id, ping);
 482
 483   VLOG(2) << download_url << " written to " << path.value();
 484
 485   FetchedCRXFile fetched(id, path, file_ownership_passed, download_url,
 486                          request_ids);
 487   fetched_crx_files_.push(fetched);
 488
 489   // MaybeInstallCRXFile() removes extensions from |in_progress_ids_| after
 490   // starting the crx installer.
 491   MaybeInstallCRXFile();
 492 }
 493
 494 bool ExtensionUpdater::GetPingDataForExtension(
 495     const std::string& id,
 496     ManifestFetchData::PingData* ping_data) {
 497   DCHECK(alive_);
 498   ping_data->rollcall_days = CalculatePingDays(
 499       extension_prefs_->LastPingDay(id));
 500   ping_data->is_enabled = service_->IsExtensionEnabled(id);
 501   ping_data->active_days =
 502       CalculateActivePingDays(extension_prefs_->LastActivePingDay(id),
 503                               extension_prefs_->GetActiveBit(id));
 504   return true;
 505 }
 506
 507 std::string ExtensionUpdater::GetUpdateUrlData(const std::string& id) {
 508   DCHECK(alive_);
 509   return extension::GetUpdateURLData(extension_prefs_, id);
 510 }
 511
 512 bool ExtensionUpdater::IsExtensionPending(const std::string& id) {
 513   DCHECK(alive_);
 514   return service_->pending_extension_manager()->IsIdPending(id);
 515 }
 516
 517 bool ExtensionUpdater::GetExtensionExistingVersion(const std::string& id,
 518                                                    std::string* version) {
 519   DCHECK(alive_);
 520   const Extension* extension = service_->GetExtensionById(id, true);
 521   if (!extension)
 522     return false;
 523   const Extension* update = service_->GetPendingExtensionUpdate(id);
 524   if (update)
 525     *version = update->VersionString();
 526   else
 527     *version = extension->VersionString();
 528   return true;
 529 }
 530
 531 void ExtensionUpdater::UpdatePingData(const std::string& id,
 532                                       const PingResult& ping_result) {
 533   DCHECK(alive_);
 534   if (ping_result.did_ping)
 535     extension_prefs_->SetLastPingDay(id, ping_result.day_start);
 536   if (extension_prefs_->GetActiveBit(id)) {
 537     extension_prefs_->SetActiveBit(id, false);
 538     extension_prefs_->SetLastActivePingDay(id, ping_result.day_start);
 539   }
 540 }
 541
 542 void ExtensionUpdater::MaybeInstallCRXFile() {
 543   if (crx_install_is_running_ || fetched_crx_files_.empty())
 544     return;
 545
 546   std::set<int> request_ids;
 547
 548   while (!fetched_crx_files_.empty() && !crx_install_is_running_) {
 549     const FetchedCRXFile& crx_file = fetched_crx_files_.top();
 550
 551     VLOG(2) << "updating " << crx_file.extension_id
 552             << " with " << crx_file.path.value();
 553
 554     // The ExtensionService is now responsible for cleaning up the temp file
 555     // at |crx_file.path|.
 556     CrxInstaller* installer = NULL;
 557     if (service_->UpdateExtension(crx_file.extension_id,
 558                                   crx_file.path,
 559                                   crx_file.file_ownership_passed,
 560                                   crx_file.download_url,
 561                                   &installer)) {
 562       crx_install_is_running_ = true;
 563       current_crx_file_ = crx_file;
 564
 565       for (std::set<int>::const_iterator it = crx_file.request_ids.begin();
 566           it != crx_file.request_ids.end(); ++it) {
 567         InProgressCheck& request = requests_in_progress_[*it];
 568         if (request.install_immediately) {
 569           installer->set_install_wait_for_idle(false);
 570           break;
 571         }
 572       }
 573
 574       // Source parameter ensures that we only see the completion event for the
 575       // the installer we started.
 576       registrar_.Add(this,
 577                      chrome::NOTIFICATION_CRX_INSTALLER_DONE,
 578                      content::Source<CrxInstaller>(installer));
 579     } else {
 580       for (std::set<int>::const_iterator it = crx_file.request_ids.begin();
 581            it != crx_file.request_ids.end(); ++it) {
 582         InProgressCheck& request = requests_in_progress_[*it];
 583         request.in_progress_ids_.remove(crx_file.extension_id);
 584       }
 585       request_ids.insert(crx_file.request_ids.begin(),
 586                          crx_file.request_ids.end());
 587     }
 588     fetched_crx_files_.pop();
 589   }
 590
 591   for (std::set<int>::const_iterator it = request_ids.begin();
 592        it != request_ids.end(); ++it) {
 593     NotifyIfFinished(*it);
 594   }
 595 }
 596
 597 void ExtensionUpdater::Observe(int type,
 598                                const content::NotificationSource& source,
 599                                const content::NotificationDetails& details) {
 600   switch (type) {
 601     case chrome::NOTIFICATION_CRX_INSTALLER_DONE: {
 602       // No need to listen for CRX_INSTALLER_DONE anymore.
 603       registrar_.Remove(this,
 604                         chrome::NOTIFICATION_CRX_INSTALLER_DONE,
 605                         source);
 606       crx_install_is_running_ = false;
 607
 608       const FetchedCRXFile& crx_file = current_crx_file_;
 609       for (std::set<int>::const_iterator it = crx_file.request_ids.begin();
 610           it != crx_file.request_ids.end(); ++it) {
 611         InProgressCheck& request = requests_in_progress_[*it];
 612         request.in_progress_ids_.remove(crx_file.extension_id);
 613         NotifyIfFinished(*it);
 614       }
 615
 616       // If any files are available to update, start one.
 617       MaybeInstallCRXFile();
 618       break;
 619     }
 620     case chrome::NOTIFICATION_EXTENSION_INSTALLED: {
 621       const Extension* extension =
 622           content::Details<const InstalledExtensionInfo>(details)->extension;
 623       if (extension)
 624         throttle_info_.erase(extension->id());
 625       break;
 626     }
 627     default:
 628       NOTREACHED();
 629   }
 630 }
 631
 632 void ExtensionUpdater::NotifyStarted() {
 633   content::NotificationService::current()->Notify(
 634       chrome::NOTIFICATION_EXTENSION_UPDATING_STARTED,
 635       content::Source<Profile>(profile_),
 636       content::NotificationService::NoDetails());
 637 }
 638
 639 void ExtensionUpdater::NotifyIfFinished(int request_id) {
 640   DCHECK(ContainsKey(requests_in_progress_, request_id));
 641   const InProgressCheck& request = requests_in_progress_[request_id];
 642   if (request.in_progress_ids_.empty()) {
 643     VLOG(2) << "Finished update check " << request_id;
 644     if (!request.callback.is_null())
 645       request.callback.Run();
 646     requests_in_progress_.erase(request_id);
 647   }
 648 }
 649
 650 }  // namespace extensions