text: // Copyright 2015 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 "chrome/browser/ui/webui/browsing_history_handler.h"
  
  #include <stddef.h>
  
  #include <set>
  #include <utility>
  
  #include "base/bind.h"
  #include "base/bind_helpers.h"
  #include "base/i18n/rtl.h"
  #include "base/i18n/time_formatting.h"
  #include "base/metrics/histogram.h"
  #include "base/strings/string16.h"
  #include "base/strings/string_number_conversions.h"
  #include "base/strings/utf_string_conversions.h"
  #include "base/time/time.h"
  #include "base/values.h"
  #include "chrome/browser/banners/app_banner_settings_helper.h"
  #include "chrome/browser/bookmarks/bookmark_model_factory.h"
  #include "chrome/browser/engagement/site_engagement_service.h"
  #include "chrome/browser/favicon/fallback_icon_service_factory.h"
  #include "chrome/browser/favicon/large_icon_service_factory.h"
  #include "chrome/browser/history/history_service_factory.h"
  #include "chrome/browser/history/history_utils.h"
  #include "chrome/browser/history/web_history_service_factory.h"
  #include "chrome/browser/profiles/profile.h"
  #include "chrome/browser/sync/profile_sync_service_factory.h"
  #include "chrome/browser/ui/browser_finder.h"
  #include "chrome/browser/ui/chrome_pages.h"
  #include "chrome/browser/ui/webui/favicon_source.h"
  #include "chrome/browser/ui/webui/large_icon_source.h"
  #include "chrome/common/features.h"
  #include "chrome/common/pref_names.h"
  #include "components/bookmarks/browser/bookmark_model.h"
  #include "components/bookmarks/browser/bookmark_utils.h"
  #include "components/browser_sync/browser/profile_sync_service.h"
  #include "components/browsing_data_ui/history_notice_utils.h"
  #include "components/favicon/core/fallback_icon_service.h"
  #include "components/favicon/core/fallback_url_util.h"
  #include "components/favicon/core/large_icon_service.h"
  #include "components/history/core/browser/history_service.h"
  #include "components/history/core/browser/history_types.h"
  #include "components/history/core/browser/web_history_service.h"
  #include "components/keyed_service/core/service_access_type.h"
  #include "components/prefs/pref_service.h"
  #include "components/query_parser/snippet.h"
  #include "components/sync_driver/device_info.h"
  #include "components/sync_driver/device_info_tracker.h"
  #include "components/url_formatter/url_formatter.h"
  #include "content/public/browser/url_data_source.h"
  #include "content/public/browser/web_ui.h"
  #include "grit/components_strings.h"
  #include "sync/protocol/history_delete_directive_specifics.pb.h"
  #include "sync/protocol/sync_enums.pb.h"
  #include "ui/base/l10n/l10n_util.h"
  #include "ui/base/l10n/time_format.h"
  
  #if defined(ENABLE_EXTENSIONS)
  #include "chrome/browser/extensions/activity_log/activity_log.h"
  #endif
  
  #if defined(ENABLE_SUPERVISED_USERS)
  #include "chrome/browser/supervised_user/supervised_user_navigation_observer.h"
  #include "chrome/browser/supervised_user/supervised_user_service.h"
  #include "chrome/browser/supervised_user/supervised_user_service_factory.h"
  #include "chrome/browser/supervised_user/supervised_user_url_filter.h"
  #endif
  
  #if BUILDFLAG(ANDROID_JAVA_UI)
  #include "chrome/browser/android/chrome_application.h"
  #endif
  
  // The amount of time to wait for a response from the WebHistoryService.
  static const int kWebHistoryTimeoutSeconds = 3;
  
  using bookmarks::BookmarkModel;
  
  namespace {
  
  // Buckets for UMA histograms.
  enum WebHistoryQueryBuckets {
    WEB_HISTORY_QUERY_FAILED = 0,
    WEB_HISTORY_QUERY_SUCCEEDED,
    WEB_HISTORY_QUERY_TIMED_OUT,
    NUM_WEB_HISTORY_QUERY_BUCKETS
  };
  
  // Identifiers for the type of device from which a history entry originated.
  static const char kDeviceTypeLaptop[] = "laptop";
  static const char kDeviceTypePhone[] = "phone";
  static const char kDeviceTypeTablet[] = "tablet";
  
  // Returns a localized version of |visit_time| including a relative
  // indicator (e.g. today, yesterday).
  base::string16 GetRelativeDateLocalized(const base::Time& visit_time) {
    base::Time midnight = base::Time::Now().LocalMidnight();
    base::string16 date_str = ui::TimeFormat::RelativeDate(visit_time, &midnight);
    if (date_str.empty()) {
      date_str = base::TimeFormatFriendlyDate(visit_time);
    } else {
      date_str = l10n_util::GetStringFUTF16(
          IDS_HISTORY_DATE_WITH_RELATIVE_TIME,
          date_str,
          base::TimeFormatFriendlyDate(visit_time));
    }
    return date_str;
  }
  
  // Sets the correct year when substracting months from a date.
  void NormalizeMonths(base::Time::Exploded* exploded) {
    // Decrease a year at a time until we have a proper date.
    while (exploded->month < 1) {
      exploded->month += 12;
      exploded->year--;
    }
  }
  
  // Returns true if |entry| represents a local visit that had no corresponding
  // visit on the server.
  bool IsLocalOnlyResult(const BrowsingHistoryHandler::HistoryEntry& entry) {
    return entry.entry_type == BrowsingHistoryHandler::HistoryEntry::LOCAL_ENTRY;
  }
  
  // Gets the name and type of a device for the given sync client ID.
  // |name| and |type| are out parameters.
  void GetDeviceNameAndType(const ProfileSyncService* sync_service,
                            const std::string& client_id,
                            std::string* name,
                            std::string* type) {
    // DeviceInfoTracker must be syncing in order for remote history entries to
    // be available.
    DCHECK(sync_service);
    DCHECK(sync_service->GetDeviceInfoTracker());
    DCHECK(sync_service->GetDeviceInfoTracker()->IsSyncing());
  
    std::unique_ptr<sync_driver::DeviceInfo> device_info =
        sync_service->GetDeviceInfoTracker()->GetDeviceInfo(client_id);
    if (device_info.get()) {
      *name = device_info->client_name();
      switch (device_info->device_type()) {
        case sync_pb::SyncEnums::TYPE_PHONE:
          *type = kDeviceTypePhone;
          break;
        case sync_pb::SyncEnums::TYPE_TABLET:
          *type = kDeviceTypeTablet;
          break;
        default:
          *type = kDeviceTypeLaptop;
      }
      return;
    }
  
    *name = l10n_util::GetStringUTF8(IDS_HISTORY_UNKNOWN_DEVICE);
    *type = kDeviceTypeLaptop;
  }
  
  void RecordMetricsForNoticeAboutOtherFormsOfBrowsingHistory(bool shown) {
    UMA_HISTOGRAM_BOOLEAN(
        "History.ShownHeaderAboutOtherFormsOfBrowsingHistory",
        shown);
  }
  
  }  // namespace
  
  BrowsingHistoryHandler::HistoryEntry::HistoryEntry(
      BrowsingHistoryHandler::HistoryEntry::EntryType entry_type,
      const GURL& url, const base::string16& title, base::Time time,
      const std::string& client_id, bool is_search_result,
      const base::string16& snippet, bool blocked_visit) {
    this->entry_type = entry_type;
    this->url = url;
    this->title = title;
    this->time = time;
    this->client_id = client_id;
    all_timestamps.insert(time.ToInternalValue());
    this->is_search_result = is_search_result;
    this->snippet = snippet;
    this->blocked_visit = blocked_visit;
  }
  
  BrowsingHistoryHandler::HistoryEntry::HistoryEntry()
      : entry_type(EMPTY_ENTRY), is_search_result(false), blocked_visit(false) {
  }
  
  BrowsingHistoryHandler::HistoryEntry::HistoryEntry(const HistoryEntry& other) =
      default;
  
  BrowsingHistoryHandler::HistoryEntry::~HistoryEntry() {
  }
  
  void BrowsingHistoryHandler::HistoryEntry::SetUrlAndTitle(
      base::DictionaryValue* result) const {
    result->SetString("url", url.spec());
  
    bool using_url_as_the_title = false;
    base::string16 title_to_set(title);
    if (title.empty()) {
      using_url_as_the_title = true;
      title_to_set = base::UTF8ToUTF16(url.spec());
    }
  
    // Since the title can contain BiDi text, we need to mark the text as either
    // RTL or LTR, depending on the characters in the string. If we use the URL
    // as the title, we mark the title as LTR since URLs are always treated as
    // left to right strings.
    if (base::i18n::IsRTL()) {
      if (using_url_as_the_title)
        base::i18n::WrapStringWithLTRFormatting(&title_to_set);
      else
        base::i18n::AdjustStringForLocaleDirection(&title_to_set);
    }
    result->SetString("title", title_to_set);
  }
  
  std::unique_ptr<base::DictionaryValue>
  BrowsingHistoryHandler::HistoryEntry::ToValue(
      BookmarkModel* bookmark_model,
      SupervisedUserService* supervised_user_service,
      const ProfileSyncService* sync_service) const {
    std::unique_ptr<base::DictionaryValue> result(new base::DictionaryValue());
    SetUrlAndTitle(result.get());
  
    base::string16 domain = url_formatter::IDNToUnicode(url.host());
    // When the domain is empty, use the scheme instead. This allows for a
    // sensible treatment of e.g. file: URLs when group by domain is on.
    if (domain.empty())
      domain = base::UTF8ToUTF16(url.scheme() + ":");
  
    // The items which are to be written into result are also described in
    // chrome/browser/resources/history/history.js in @typedef for
    // HistoryEntry. Please update it whenever you add or remove
    // any keys in result.
    result->SetString("domain", domain);
  
    result->SetString("fallbackFaviconText",
                      base::UTF16ToASCII(favicon::GetFallbackIconText(url)));
  
    result->SetDouble("time", time.ToJsTime());
  
    // Pass the timestamps in a list.
    std::unique_ptr<base::ListValue> timestamps(new base::ListValue);
    for (std::set<int64_t>::const_iterator it = all_timestamps.begin();
         it != all_timestamps.end(); ++it) {
      timestamps->AppendDouble(base::Time::FromInternalValue(*it).ToJsTime());
    }
    result->Set("allTimestamps", timestamps.release());
  
    // Always pass the short date since it is needed both in the search and in
    // the monthly view.
    result->SetString("dateShort", base::TimeFormatShortDate(time));
  
    base::string16 snippet_string;
    base::string16 date_relative_day;
    base::string16 date_time_of_day;
    bool is_blocked_visit = false;
    int host_filtering_behavior = -1;
  
    // Only pass in the strings we need (search results need a shortdate
    // and snippet, browse results need day and time information). Makes sure that
    // values of result are never undefined
    if (is_search_result) {
      snippet_string = snippet;
    } else {
      base::Time midnight = base::Time::Now().LocalMidnight();
      base::string16 date_str = ui::TimeFormat::RelativeDate(time, &midnight);
      if (date_str.empty()) {
        date_str = base::TimeFormatFriendlyDate(time);
      } else {
        date_str = l10n_util::GetStringFUTF16(
            IDS_HISTORY_DATE_WITH_RELATIVE_TIME,
            date_str,
            base::TimeFormatFriendlyDate(time));
      }
      date_relative_day = date_str;
      date_time_of_day = base::TimeFormatTimeOfDay(time);
    }
  
    std::string device_name;
    std::string device_type;
    if (!client_id.empty())
      GetDeviceNameAndType(sync_service, client_id, &device_name, &device_type);
    result->SetString("deviceName", device_name);
    result->SetString("deviceType", device_type);
  
  #if defined(ENABLE_SUPERVISED_USERS)
    if (supervised_user_service) {
      const SupervisedUserURLFilter* url_filter =
          supervised_user_service->GetURLFilterForUIThread();
      int filtering_behavior =
          url_filter->GetFilteringBehaviorForURL(url.GetWithEmptyPath());
      is_blocked_visit = blocked_visit;
      host_filtering_behavior = filtering_behavior;
    }
  #endif
  
    result->SetString("dateTimeOfDay", date_time_of_day);
    result->SetString("dateRelativeDay", date_relative_day);
    result->SetString("snippet", snippet_string);
    result->SetBoolean("starred", bookmark_model->IsBookmarked(url));
    result->SetInteger("hostFilteringBehavior", host_filtering_behavior);
    result->SetBoolean("blockedVisit", is_blocked_visit);
  
    return result;
  }
  
  bool BrowsingHistoryHandler::HistoryEntry::SortByTimeDescending(
      const BrowsingHistoryHandler::HistoryEntry& entry1,
      const BrowsingHistoryHandler::HistoryEntry& entry2) {
    return entry1.time > entry2.time;
  }
  
  BrowsingHistoryHandler::BrowsingHistoryHandler()
      : has_pending_delete_request_(false),
        history_service_observer_(this),
        has_synced_results_(false),
        has_other_forms_of_browsing_history_(false),
        weak_factory_(this) {
  }
  
  BrowsingHistoryHandler::~BrowsingHistoryHandler() {
    query_task_tracker_.TryCancelAll();
    web_history_request_.reset();
  }
  
  void BrowsingHistoryHandler::RegisterMessages() {
    // Create our favicon data source.
    Profile* profile = Profile::FromWebUI(web_ui());
  
  #if defined(OS_ANDROID)
    favicon::FallbackIconService* fallback_icon_service =
        FallbackIconServiceFactory::GetForBrowserContext(profile);
    favicon::LargeIconService* large_icon_service =
        LargeIconServiceFactory::GetForBrowserContext(profile);
    content::URLDataSource::Add(
        profile, new LargeIconSource(fallback_icon_service, large_icon_service));
  #else
    content::URLDataSource::Add(
        profile, new FaviconSource(profile, FaviconSource::ANY));
  #endif
  
    // Get notifications when history is cleared.
    history::HistoryService* hs = HistoryServiceFactory::GetForProfile(
        profile, ServiceAccessType::EXPLICIT_ACCESS);
    if (hs)
      history_service_observer_.Add(hs);
  
    web_ui()->RegisterMessageCallback("queryHistory",
        base::Bind(&BrowsingHistoryHandler::HandleQueryHistory,
                   base::Unretained(this)));
    web_ui()->RegisterMessageCallback("removeVisits",
        base::Bind(&BrowsingHistoryHandler::HandleRemoveVisits,
                   base::Unretained(this)));
    web_ui()->RegisterMessageCallback("clearBrowsingData",
        base::Bind(&BrowsingHistoryHandler::HandleClearBrowsingData,
                   base::Unretained(this)));
    web_ui()->RegisterMessageCallback("removeBookmark",
        base::Bind(&BrowsingHistoryHandler::HandleRemoveBookmark,
                   base::Unretained(this)));
  }
  
  bool BrowsingHistoryHandler::ExtractIntegerValueAtIndex(
      const base::ListValue* value,
      int index,
      int* out_int) {
    double double_value;
    if (value->GetDouble(index, &double_value)) {
      *out_int = static_cast<int>(double_value);
      return true;
    }
    NOTREACHED();
    return false;
  }
  
  void BrowsingHistoryHandler::WebHistoryTimeout() {
    // TODO(dubroy): Communicate the failure to the front end.
    if (!query_task_tracker_.HasTrackedTasks())
      ReturnResultsToFrontEnd();
  
    UMA_HISTOGRAM_ENUMERATION(
        "WebHistory.QueryCompletion",
        WEB_HISTORY_QUERY_TIMED_OUT, NUM_WEB_HISTORY_QUERY_BUCKETS);
  }
  
  void BrowsingHistoryHandler::QueryHistory(
      const base::string16& search_text,
      const history::QueryOptions& options) {
    Profile* profile = Profile::FromWebUI(web_ui());
  
    // Anything in-flight is invalid.
    query_task_tracker_.TryCancelAll();
    web_history_request_.reset();
  
    query_results_.clear();
    results_info_value_.Clear();
    has_synced_results_ = false;
    has_other_forms_of_browsing_history_ = false;
  
    history::HistoryService* hs = HistoryServiceFactory::GetForProfile(
        profile, ServiceAccessType::EXPLICIT_ACCESS);
    hs->QueryHistory(search_text,
                     options,
                     base::Bind(&BrowsingHistoryHandler::QueryComplete,
                                base::Unretained(this),
                                search_text,
                                options),
                     &query_task_tracker_);
  
    history::WebHistoryService* web_history =
        WebHistoryServiceFactory::GetForProfile(profile);
  
    // Set this to false until the results actually arrive.
    results_info_value_.SetBoolean("hasSyncedResults", false);
  
    if (web_history) {
      web_history_query_results_.clear();
      web_history_request_ = web_history->QueryHistory(
          search_text,
          options,
          base::Bind(&BrowsingHistoryHandler::WebHistoryQueryComplete,
                     base::Unretained(this),
                     search_text, options,
                     base::TimeTicks::Now()));
      // Start a timer so we know when to give up.
      web_history_timer_.Start(
          FROM_HERE, base::TimeDelta::FromSeconds(kWebHistoryTimeoutSeconds),
          this, &BrowsingHistoryHandler::WebHistoryTimeout);
  
      // Test the existence of other forms of browsing history.
      browsing_data_ui::ShouldShowNoticeAboutOtherFormsOfBrowsingHistory(
          ProfileSyncServiceFactory::GetInstance()->GetForProfile(profile),
          web_history,
          base::Bind(
              &BrowsingHistoryHandler::OtherFormsOfBrowsingHistoryQueryComplete,
              weak_factory_.GetWeakPtr()));
    } else {
      // The notice could not have been shown, because there is no web history.
      RecordMetricsForNoticeAboutOtherFormsOfBrowsingHistory(false);
    }
  }
  
  void BrowsingHistoryHandler::HandleQueryHistory(const base::ListValue* args) {
    history::QueryOptions options;
  
    // Parse the arguments from JavaScript. There are five required arguments:
    // - the text to search for (may be empty)
    // - the offset from which the search should start (in multiples of week or
    //   month, set by the next argument).
    // - the range (BrowsingHistoryHandler::Range) Enum value that sets the range
    //   of the query.
    // - the end time for the query. Only results older than this time will be
    //   returned.
    // - the maximum number of results to return (may be 0, meaning that there
    //   is no maximum).
    base::string16 search_text = ExtractStringValue(args);
    int offset;
    if (!args->GetInteger(1, &offset)) {
      NOTREACHED() << "Failed to convert argument 1. ";
      return;
    }
    int range;
    if (!args->GetInteger(2, &range)) {
      NOTREACHED() << "Failed to convert argument 2. ";
      return;
    }
  
    if (range == BrowsingHistoryHandler::MONTH)
      SetQueryTimeInMonths(offset, &options);
    else if (range == BrowsingHistoryHandler::WEEK)
      SetQueryTimeInWeeks(offset, &options);
  
    double end_time;
    if (!args->GetDouble(3, &end_time)) {
      NOTREACHED() << "Failed to convert argument 3. ";
      return;
    }
    if (end_time)
      options.end_time = base::Time::FromJsTime(end_time);
  
    if (!ExtractIntegerValueAtIndex(args, 4, &options.max_count)) {
      NOTREACHED() << "Failed to convert argument 4.";
      return;
    }
  
    options.duplicate_policy = history::QueryOptions::REMOVE_DUPLICATES_PER_DAY;
    QueryHistory(search_text, options);
  }
  
  void BrowsingHistoryHandler::HandleRemoveVisits(const base::ListValue* args) {
    Profile* profile = Profile::FromWebUI(web_ui());
    // TODO(davidben): history.js is not aware of this failure and will still
    // override |deleteCompleteCallback_|.
    if (delete_task_tracker_.HasTrackedTasks() ||
        has_pending_delete_request_ ||
        !profile->GetPrefs()->GetBoolean(prefs::kAllowDeletingBrowserHistory)) {
      web_ui()->CallJavascriptFunctionUnsafe("deleteFailed");
      return;
    }
  
    history::HistoryService* history_service =
        HistoryServiceFactory::GetForProfile(profile,
                                             ServiceAccessType::EXPLICIT_ACCESS);
    history::WebHistoryService* web_history =
        WebHistoryServiceFactory::GetForProfile(profile);
  
    base::Time now = base::Time::Now();
    std::vector<history::ExpireHistoryArgs> expire_list;
    expire_list.reserve(args->GetSize());
  
    DCHECK(urls_to_be_deleted_.empty());
    for (base::ListValue::const_iterator it = args->begin();
         it != args->end(); ++it) {
      base::DictionaryValue* deletion = NULL;
      base::string16 url;
      base::ListValue* timestamps = NULL;
  
      // Each argument is a dictionary with properties "url" and "timestamps".
      if (!((*it)->GetAsDictionary(&deletion) &&
          deletion->GetString("url", &url) &&
          deletion->GetList("timestamps", &timestamps))) {
        NOTREACHED() << "Unable to extract arguments";
        return;
      }
      DCHECK(timestamps->GetSize() > 0);
  
      // In order to ensure that visits will be deleted from the server and other
      // clients (even if they are offline), create a sync delete directive for
      // each visit to be deleted.
      sync_pb::HistoryDeleteDirectiveSpecifics delete_directive;
      sync_pb::GlobalIdDirective* global_id_directive =
          delete_directive.mutable_global_id_directive();
  
      double timestamp;
      history::ExpireHistoryArgs* expire_args = NULL;
      for (base::ListValue::const_iterator ts_iterator = timestamps->begin();
           ts_iterator != timestamps->end(); ++ts_iterator) {
        if (!(*ts_iterator)->GetAsDouble(&timestamp)) {
          NOTREACHED() << "Unable to extract visit timestamp.";
          continue;
        }
        base::Time visit_time = base::Time::FromJsTime(timestamp);
        if (!expire_args) {
          GURL gurl(url);
          expire_list.resize(expire_list.size() + 1);
          expire_args = &expire_list.back();
          expire_args->SetTimeRangeForOneDay(visit_time);
          expire_args->urls.insert(gurl);
          urls_to_be_deleted_.insert(gurl);
        }
        // The local visit time is treated as a global ID for the visit.
        global_id_directive->add_global_id(visit_time.ToInternalValue());
      }
  
      // Set the start and end time in microseconds since the Unix epoch.
      global_id_directive->set_start_time_usec(
          (expire_args->begin_time - base::Time::UnixEpoch()).InMicroseconds());
  
      // Delete directives shouldn't have an end time in the future.
      // TODO(dubroy): Use sane time (crbug.com/146090) here when it's ready.
      base::Time end_time = std::min(expire_args->end_time, now);
  
      // -1 because end time in delete directives is inclusive.
      global_id_directive->set_end_time_usec(
          (end_time - base::Time::UnixEpoch()).InMicroseconds() - 1);
  
      // TODO(dubroy): Figure out the proper way to handle an error here.
      if (web_history)
        history_service->ProcessLocalDeleteDirective(delete_directive);
    }
  
    history_service->ExpireHistory(
        expire_list,
        base::Bind(&BrowsingHistoryHandler::RemoveComplete,
                   base::Unretained(this)),
        &delete_task_tracker_);
  
    if (web_history) {
      has_pending_delete_request_ = true;
      web_history->ExpireHistory(
          expire_list,
          base::Bind(&BrowsingHistoryHandler::RemoveWebHistoryComplete,
                     weak_factory_.GetWeakPtr()));
    }
  
  #if defined(ENABLE_EXTENSIONS)
    // If the profile has activity logging enabled also clean up any URLs from
    // the extension activity log. The extension activity log contains URLS
    // which websites an extension has activity on so it will indirectly
    // contain websites that a user has visited.
    extensions::ActivityLog* activity_log =
        extensions::ActivityLog::GetInstance(profile);
    for (std::vector<history::ExpireHistoryArgs>::const_iterator it =
         expire_list.begin(); it != expire_list.end(); ++it) {
      activity_log->RemoveURLs(it->urls);
    }
  #endif
  
    for (const history::ExpireHistoryArgs& expire_entry : expire_list)
      AppBannerSettingsHelper::ClearHistoryForURLs(profile, expire_entry.urls);
  }
  
  void BrowsingHistoryHandler::HandleClearBrowsingData(
      const base::ListValue* args) {
  #if BUILDFLAG(ANDROID_JAVA_UI)
    chrome::android::ChromeApplication::OpenClearBrowsingData(
        web_ui()->GetWebContents());
  #else
    // TODO(beng): This is an improper direct dependency on Browser. Route this
    // through some sort of delegate.
    Browser* browser = chrome::FindBrowserWithWebContents(
        web_ui()->GetWebContents());
    chrome::ShowClearBrowsingDataDialog(browser);
  #endif
  }
  
  void BrowsingHistoryHandler::HandleRemoveBookmark(const base::ListValue* args) {
    base::string16 url = ExtractStringValue(args);
    Profile* profile = Profile::FromWebUI(web_ui());
    BookmarkModel* model = BookmarkModelFactory::GetForProfile(profile);
    bookmarks::RemoveAllBookmarks(model, GURL(url));
  }
  
  // static
  void BrowsingHistoryHandler::MergeDuplicateResults(
      std::vector<BrowsingHistoryHandler::HistoryEntry>* results) {
    std::vector<BrowsingHistoryHandler::HistoryEntry> new_results;
    // Pre-reserve the size of the new vector. Since we're working with pointers
    // later on not doing this could lead to the vector being resized and to
    // pointers to invalid locations.
    new_results.reserve(results->size());
    // Maps a URL to the most recent entry on a particular day.
    std::map<GURL, BrowsingHistoryHandler::HistoryEntry*> current_day_entries;
  
    // Keeps track of the day that |current_day_urls| is holding the URLs for,
    // in order to handle removing per-day duplicates.
    base::Time current_day_midnight;
  
    std::sort(
        results->begin(), results->end(), HistoryEntry::SortByTimeDescending);
  
    for (std::vector<BrowsingHistoryHandler::HistoryEntry>::const_iterator it =
             results->begin(); it != results->end(); ++it) {
      // Reset the list of found URLs when a visit from a new day is encountered.
      if (current_day_midnight != it->time.LocalMidnight()) {
        current_day_entries.clear();
        current_day_midnight = it->time.LocalMidnight();
      }
  
      // Keep this visit if it's the first visit to this URL on the current day.
      if (current_day_entries.count(it->url) == 0) {
        new_results.push_back(*it);
        current_day_entries[it->url] = &new_results.back();
      } else {
        // Keep track of the timestamps of all visits to the URL on the same day.
        BrowsingHistoryHandler::HistoryEntry* entry =
            current_day_entries[it->url];
        entry->all_timestamps.insert(
            it->all_timestamps.begin(), it->all_timestamps.end());
  
        if (entry->entry_type != it->entry_type) {
          entry->entry_type =
              BrowsingHistoryHandler::HistoryEntry::COMBINED_ENTRY;
        }
      }
    }
    results->swap(new_results);
  }
  
  void BrowsingHistoryHandler::ReturnResultsToFrontEnd() {
    Profile* profile = Profile::FromWebUI(web_ui());
    BookmarkModel* bookmark_model = BookmarkModelFactory::GetForProfile(profile);
    SupervisedUserService* supervised_user_service = NULL;
  #if defined(ENABLE_SUPERVISED_USERS)
    if (profile->IsSupervised())
      supervised_user_service =
          SupervisedUserServiceFactory::GetForProfile(profile);
  #endif
    ProfileSyncService* sync_service =
        ProfileSyncServiceFactory::GetInstance()->GetForProfile(profile);
  
    // Combine the local and remote results into |query_results_|, and remove
    // any duplicates.
    if (!web_history_query_results_.empty()) {
      int local_result_count = query_results_.size();
      query_results_.insert(query_results_.end(),
                            web_history_query_results_.begin(),
                            web_history_query_results_.end());
      MergeDuplicateResults(&query_results_);
  
      if (local_result_count) {
        // In the best case, we expect that all local results are duplicated on
        // the server. Keep track of how many are missing.
        int missing_count = std::count_if(
            query_results_.begin(), query_results_.end(), IsLocalOnlyResult);
        UMA_HISTOGRAM_PERCENTAGE("WebHistory.LocalResultMissingOnServer",
                                 missing_count * 100.0 / local_result_count);
      }
    }
  
    // Convert the result vector into a ListValue.
    base::ListValue results_value;
    for (std::vector<BrowsingHistoryHandler::HistoryEntry>::iterator it =
             query_results_.begin(); it != query_results_.end(); ++it) {
      std::unique_ptr<base::Value> value(
          it->ToValue(bookmark_model, supervised_user_service, sync_service));
      results_value.Append(std::move(value));
    }
  
    web_ui()->CallJavascriptFunctionUnsafe("historyResult", results_info_value_,
                                           results_value);
    web_ui()->CallJavascriptFunctionUnsafe(
        "showNotification", base::FundamentalValue(has_synced_results_),
        base::FundamentalValue(has_other_forms_of_browsing_history_));
    results_info_value_.Clear();
    query_results_.clear();
    web_history_query_results_.clear();
  }
  
  void BrowsingHistoryHandler::QueryComplete(
      const base::string16& search_text,
      const history::QueryOptions& options,
      history::QueryResults* results) {
    DCHECK_EQ(0U, query_results_.size());
    query_results_.reserve(results->size());
  
    for (size_t i = 0; i < results->size(); ++i) {
      history::URLResult const &page = (*results)[i];
      // TODO(dubroy): Use sane time (crbug.com/146090) here when it's ready.
      query_results_.push_back(
          HistoryEntry(
              HistoryEntry::LOCAL_ENTRY,
              page.url(),
              page.title(),
              page.visit_time(),
              std::string(),
              !search_text.empty(),
              page.snippet().text(),
              page.blocked_visit()));
    }
  
    // The items which are to be written into results_info_value_ are also
    // described in chrome/browser/resources/history/history.js in @typedef for
    // HistoryQuery. Please update it whenever you add or remove any keys in
    // results_info_value_.
    results_info_value_.SetString("term", search_text);
    results_info_value_.SetBoolean("finished", results->reached_beginning());
  
    // Add the specific dates that were searched to display them.
    // TODO(sergiu): Put today if the start is in the future.
    results_info_value_.SetString("queryStartTime",
                                  GetRelativeDateLocalized(options.begin_time));
    if (!options.end_time.is_null()) {
      results_info_value_.SetString("queryEndTime",
          GetRelativeDateLocalized(options.end_time -
                                   base::TimeDelta::FromDays(1)));
    } else {
      results_info_value_.SetString("queryEndTime",
          GetRelativeDateLocalized(base::Time::Now()));
    }
    if (!web_history_timer_.IsRunning())
      ReturnResultsToFrontEnd();
  }
  
  void BrowsingHistoryHandler::WebHistoryQueryComplete(
      const base::string16& search_text,
      const history::QueryOptions& options,
      base::TimeTicks start_time,
      history::WebHistoryService::Request* request,
      const base::DictionaryValue* results_value) {
    base::TimeDelta delta = base::TimeTicks::Now() - start_time;
    UMA_HISTOGRAM_TIMES("WebHistory.ResponseTime", delta);
  
    // If the response came in too late, do nothing.
    // TODO(dubroy): Maybe show a banner, and prompt the user to reload?
    if (!web_history_timer_.IsRunning())
      return;
    web_history_timer_.Stop();
  
    UMA_HISTOGRAM_ENUMERATION(
        "WebHistory.QueryCompletion",
        results_value ? WEB_HISTORY_QUERY_SUCCEEDED : WEB_HISTORY_QUERY_FAILED,
        NUM_WEB_HISTORY_QUERY_BUCKETS);
  
    DCHECK_EQ(0U, web_history_query_results_.size());
    const base::ListValue* events = NULL;
    if (results_value && results_value->GetList("event", &events)) {
      web_history_query_results_.reserve(events->GetSize());
      for (unsigned int i = 0; i < events->GetSize(); ++i) {
        const base::DictionaryValue* event = NULL;
        const base::DictionaryValue* result = NULL;
        const base::ListValue* results = NULL;
        const base::ListValue* ids = NULL;
        base::string16 url;
        base::string16 title;
        base::Time visit_time;
  
        if (!(events->GetDictionary(i, &event) &&
            event->GetList("result", &results) &&
            results->GetDictionary(0, &result) &&
            result->GetString("url", &url) &&
            result->GetList("id", &ids) &&
            ids->GetSize() > 0)) {
          LOG(WARNING) << "Improperly formed JSON response from history server.";
          continue;
        }
  
        // Ignore any URLs that should not be shown in the history page.
        GURL gurl(url);
        if (!CanAddURLToHistory(gurl))
          continue;
  
        // Title is optional, so the return value is ignored here.
        result->GetString("title", &title);
  
        // Extract the timestamps of all the visits to this URL.
        // They are referred to as "IDs" by the server.
        for (int j = 0; j < static_cast<int>(ids->GetSize()); ++j) {
          const base::DictionaryValue* id = NULL;
          std::string timestamp_string;
          int64_t timestamp_usec = 0;
  
          if (!ids->GetDictionary(j, &id) ||
              !id->GetString("timestamp_usec", &timestamp_string) ||
              !base::StringToInt64(timestamp_string, &timestamp_usec)) {
            NOTREACHED() << "Unable to extract timestamp.";
            continue;
          }
          // The timestamp on the server is a Unix time.
          base::Time time = base::Time::UnixEpoch() +
              base::TimeDelta::FromMicroseconds(timestamp_usec);
  
          // Get the ID of the client that this visit came from.
          std::string client_id;
          id->GetString("client_id", &client_id);
  
          web_history_query_results_.push_back(
              HistoryEntry(
                  HistoryEntry::REMOTE_ENTRY,
                  gurl,
                  title,
                  time,
                  client_id,
                  !search_text.empty(),
                  base::string16(),
                  /* blocked_visit */ false));
        }
      }
    }
    has_synced_results_ = results_value != nullptr;
    results_info_value_.SetBoolean("hasSyncedResults", has_synced_results_);
    if (!query_task_tracker_.HasTrackedTasks())
      ReturnResultsToFrontEnd();
  }
  
  void BrowsingHistoryHandler::OtherFormsOfBrowsingHistoryQueryComplete(
      bool found_other_forms_of_browsing_history) {
    has_other_forms_of_browsing_history_ = found_other_forms_of_browsing_history;
  
    RecordMetricsForNoticeAboutOtherFormsOfBrowsingHistory(
        has_other_forms_of_browsing_history_);
  
    web_ui()->CallJavascriptFunctionUnsafe(
        "showNotification", base::FundamentalValue(has_synced_results_),
        base::FundamentalValue(has_other_forms_of_browsing_history_));
  }
  
  void BrowsingHistoryHandler::RemoveComplete() {
    urls_to_be_deleted_.clear();
  
    // Notify the page that the deletion request is complete, but only if a web
    // history delete request is not still pending.
    if (!has_pending_delete_request_)
      web_ui()->CallJavascriptFunctionUnsafe("deleteComplete");
  }
  
  void BrowsingHistoryHandler::RemoveWebHistoryComplete(bool success) {
    has_pending_delete_request_ = false;
    // TODO(dubroy): Should we handle failure somehow? Delete directives will
    // ensure that the visits are eventually deleted, so maybe it's not necessary.
    if (!delete_task_tracker_.HasTrackedTasks())
      RemoveComplete();
  }
  
  void BrowsingHistoryHandler::SetQueryTimeInWeeks(
      int offset, history::QueryOptions* options) {
    // LocalMidnight returns the beginning of the current day so get the
    // beginning of the next one.
    base::Time midnight = base::Time::Now().LocalMidnight() +
                                base::TimeDelta::FromDays(1);
    options->end_time = midnight -
        base::TimeDelta::FromDays(7 * offset);
    options->begin_time = midnight -
        base::TimeDelta::FromDays(7 * (offset + 1));
  }
  
  void BrowsingHistoryHandler::SetQueryTimeInMonths(
      int offset, history::QueryOptions* options) {
    // Configure the begin point of the search to the start of the
    // current month.
    base::Time::Exploded exploded;
    base::Time::Now().LocalMidnight().LocalExplode(&exploded);
    exploded.day_of_month = 1;
  
    if (offset == 0) {
      options->begin_time = base::Time::FromLocalExploded(exploded);
  
      // Set the end time of this first search to null (which will
      // show results from the future, should the user's clock have
      // been set incorrectly).
      options->end_time = base::Time();
    } else {
      // Go back |offset| months in the past. The end time is not inclusive, so
      // use the first day of the |offset| - 1 and |offset| months (e.g. for
      // the last month, |offset| = 1, use the first days of the last month and
      // the current month.
      exploded.month -= offset - 1;
      // Set the correct year.
      NormalizeMonths(&exploded);
      options->end_time = base::Time::FromLocalExploded(exploded);
  
      exploded.month -= 1;
      // Set the correct year
      NormalizeMonths(&exploded);
      options->begin_time = base::Time::FromLocalExploded(exploded);
    }
  }
  
  // Helper function for Observe that determines if there are any differences
  // between the URLs noticed for deletion and the ones we are expecting.
  static bool DeletionsDiffer(const history::URLRows& deleted_rows,
                              const std::set<GURL>& urls_to_be_deleted) {
    if (deleted_rows.size() != urls_to_be_deleted.size())
      return true;
    for (const auto& i : deleted_rows) {
      if (urls_to_be_deleted.find(i.url()) == urls_to_be_deleted.end())
        return true;
    }
    return false;
  }
  
  void BrowsingHistoryHandler::OnURLsDeleted(
      history::HistoryService* history_service,
      bool all_history,
      bool expired,
      const history::URLRows& deleted_rows,
      const std::set<GURL>& favicon_urls) {
    if (all_history || DeletionsDiffer(deleted_rows, urls_to_be_deleted_))
      web_ui()->CallJavascriptFunctionUnsafe("historyDeleted");
  }
  