chrome/browser/win/jumplist.cc

// Copyright 2012 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/win/jumplist.h"

#include <utility>

#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/command_line.h"
#include "base/files/file_util.h"
#include "base/macros.h"
#include "base/metrics/histogram_macros.h"
#include "base/path_service.h"
#include "base/sequenced_task_runner.h"
#include "base/single_thread_task_runner.h"
#include "base/strings/string_util.h"
#include "base/strings/utf_string_conversions.h"
#include "base/task_scheduler/post_task.h"
#include "base/threading/thread.h"
#include "base/threading/thread_restrictions.h"
#include "base/timer/elapsed_timer.h"
#include "base/trace_event/trace_event.h"
#include "chrome/browser/chrome_notification_types.h"
#include "chrome/browser/favicon/favicon_service_factory.h"
#include "chrome/browser/history/top_sites_factory.h"
#include "chrome/browser/metrics/jumplist_metrics_win.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/sessions/tab_restore_service_factory.h"
#include "chrome/browser/shell_integration_win.h"
#include "chrome/browser/win/jumplist_file_util.h"
#include "chrome/common/chrome_constants.h"
#include "chrome/common/chrome_icon_resources_win.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/common/pref_names.h"
#include "chrome/common/url_constants.h"
#include "chrome/grit/generated_resources.h"
#include "chrome/install_static/install_util.h"
#include "components/favicon/core/favicon_service.h"
#include "components/favicon_base/favicon_types.h"
#include "components/history/core/browser/history_service.h"
#include "components/history/core/browser/page_usage_data.h"
#include "components/history/core/browser/top_sites.h"
#include "components/prefs/pref_change_registrar.h"
#include "components/sessions/core/session_types.h"
#include "components/sessions/core/tab_restore_service.h"
#include "components/strings/grit/components_strings.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/notification_registrar.h"
#include "content/public/browser/notification_source.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/gfx/codec/png_codec.h"
#include "ui/gfx/favicon_size.h"
#include "ui/gfx/icon_util.h"
#include "ui/gfx/image/image.h"
#include "ui/gfx/image/image_family.h"
#include "ui/gfx/image/image_skia.h"
#include "ui/gfx/image/image_skia_rep.h"
#include "url/gurl.h"

using content::BrowserThread;
using JumpListData = JumpList::JumpListData;

namespace {

// Delay jumplist updates to allow collapsing of redundant update requests.
constexpr base::TimeDelta kDelayForJumplistUpdate =
    base::TimeDelta::FromMilliseconds(3500);

// Timeout jumplist updates for users with extremely slow OS.
constexpr base::TimeDelta kTimeOutForJumplistUpdate =
    base::TimeDelta::FromMilliseconds(500);

// Append the common switches to each shell link.
void AppendCommonSwitches(ShellLinkItem* shell_link) {
  const char* kSwitchNames[] = { switches::kUserDataDir };
  const base::CommandLine& command_line =
      *base::CommandLine::ForCurrentProcess();
  shell_link->GetCommandLine()->CopySwitchesFrom(command_line,
                                                 kSwitchNames,
                                                 arraysize(kSwitchNames));
}

// Create a ShellLinkItem preloaded with common switches.
scoped_refptr<ShellLinkItem> CreateShellLink() {
  scoped_refptr<ShellLinkItem> link(new ShellLinkItem);
  AppendCommonSwitches(link.get());
  return link;
}

// Creates a temporary icon file to be shown in JumpList.
bool CreateIconFile(const gfx::ImageSkia& image_skia,
                    const base::FilePath& icon_dir,
                    base::FilePath* icon_path) {
  // Retrieve the path to a temporary file.
  // We don't have to care about the extension of this temporary file because
  // JumpList does not care about it.
  base::FilePath path;
  if (!base::CreateTemporaryFileInDir(icon_dir, &path))
    return false;

  // Create an icon file from the favicon attached to the given |page|, and
  // save it as the temporary file.
  gfx::ImageFamily image_family;
  if (!image_skia.isNull()) {
    std::vector<float> supported_scales = image_skia.GetSupportedScales();
    for (auto& scale : supported_scales) {
      gfx::ImageSkiaRep image_skia_rep = image_skia.GetRepresentation(scale);
      if (!image_skia_rep.is_null())
        image_family.Add(
            gfx::Image::CreateFrom1xBitmap(image_skia_rep.sk_bitmap()));
    }
  }

  if (!IconUtil::CreateIconFileFromImageFamily(image_family, path,
                                               IconUtil::NORMAL_WRITE)) {
    // Delete the file created by CreateTemporaryFileInDir as it won't be used.
    base::DeleteFile(path, false);
    return false;
  }

  // Add this icon file to the list and return its absolute path.
  // The IShellLink::SetIcon() function needs the absolute path to an icon.
  *icon_path = path;
  return true;
}

// Helper method for RunUpdate to create icon files for the asynchrounously
// loaded icons.
void CreateIconFiles(const base::FilePath& icon_dir,
                     const ShellLinkItemList& item_list,
                     size_t max_items) {
  // TODO(chengx): Remove the UMA histogram after fixing http://crbug.com/40407.
  SCOPED_UMA_HISTOGRAM_TIMER("WinJumplist.CreateIconFilesDuration");

  for (ShellLinkItemList::const_iterator item = item_list.begin();
       item != item_list.end() && max_items > 0; ++item, --max_items) {
    base::FilePath icon_path;
    if (CreateIconFile((*item)->icon_image(), icon_dir, &icon_path))
      (*item)->set_icon(icon_path.value(), 0);
  }
}

// Updates the "Tasks" category of the JumpList.
bool UpdateTaskCategory(
    JumpListUpdater* jumplist_updater,
    IncognitoModePrefs::Availability incognito_availability) {
  base::FilePath chrome_path;
  if (!PathService::Get(base::FILE_EXE, &chrome_path))
    return false;

  int icon_index = install_static::GetIconResourceIndex();

  ShellLinkItemList items;

  // Create an IShellLink object which launches Chrome, and add it to the
  // collection. We use our application icon as the icon for this item.
  // We remove '&' characters from this string so we can share it with our
  // system menu.
  if (incognito_availability != IncognitoModePrefs::FORCED) {
    scoped_refptr<ShellLinkItem> chrome = CreateShellLink();
    base::string16 chrome_title = l10n_util::GetStringUTF16(IDS_NEW_WINDOW);
    base::ReplaceSubstringsAfterOffset(
        &chrome_title, 0, L"&", base::StringPiece16());
    chrome->set_title(chrome_title);
    chrome->set_icon(chrome_path.value(), icon_index);
    items.push_back(chrome);
  }

  // Create an IShellLink object which launches Chrome in incognito mode, and
  // add it to the collection.
  if (incognito_availability != IncognitoModePrefs::DISABLED) {
    scoped_refptr<ShellLinkItem> incognito = CreateShellLink();
    incognito->GetCommandLine()->AppendSwitch(switches::kIncognito);
    base::string16 incognito_title =
        l10n_util::GetStringUTF16(IDS_NEW_INCOGNITO_WINDOW);
    base::ReplaceSubstringsAfterOffset(
        &incognito_title, 0, L"&", base::StringPiece16());
    incognito->set_title(incognito_title);
    incognito->set_icon(chrome_path.value(), icon_resources::kIncognitoIndex);
    items.push_back(incognito);
  }

  return jumplist_updater->AddTasks(items);
}

// Updates the application JumpList, which consists of 1) delete old icon files;
// 2) create new icon files; 3) notify the OS.
// Note that any timeout error along the way results in the old jumplist being
// left as-is, while any non-timeout error results in the old jumplist being
// left as-is, but without icon files.
bool UpdateJumpList(const wchar_t* app_id,
                    const base::FilePath& icon_dir,
                    const ShellLinkItemList& most_visited_pages,
                    const ShellLinkItemList& recently_closed_pages,
                    bool most_visited_pages_have_updates,
                    bool recently_closed_pages_have_updates,
                    IncognitoModePrefs::Availability incognito_availability) {
  if (!JumpListUpdater::IsEnabled())
    return true;

  // Records the time cost of starting a JumpListUpdater.
  base::ElapsedTimer begin_update_timer;

  JumpListUpdater jumplist_updater(app_id);
  if (!jumplist_updater.BeginUpdate())
    return false;

  // Stops jumplist update if JumpListUpdater's start times out, as it's very
  // likely the following update steps will also take a long time.
  if (begin_update_timer.Elapsed() >= kTimeOutForJumplistUpdate)
    return false;

  // The default maximum number of items to display in JumpList is 10.
  // https://msdn.microsoft.com/library/windows/desktop/dd378398.aspx
  // The "Most visited" category title always takes 1 of the JumpList slots if
  // |most_visited_pages| isn't empty.
  // The "Recently closed" category title will also take 1 if
  // |recently_closed_pages| isn't empty.
  // For the remaining slots, we allocate 5/8 (i.e., 5 slots if both categories
  // present) to "most-visited" items and 3/8 (i.e., 3 slots if both categories
  // present) to "recently-closed" items, respectively.
  // Nevertheless, if there are not so many items in |recently_closed_pages|,
  // we give the remaining slots to "most-visited" items.

  const int kMostVisited = 50;
  const int kRecentlyClosed = 30;
  const int kTotal = kMostVisited + kRecentlyClosed;

  // Adjust the available jumplist slots to account for the category titles.
  size_t user_max_items_adjusted = jumplist_updater.user_max_items();
  if (!most_visited_pages.empty())
    --user_max_items_adjusted;
  if (!recently_closed_pages.empty())
    --user_max_items_adjusted;

  size_t most_visited_items =
      MulDiv(user_max_items_adjusted, kMostVisited, kTotal);
  size_t recently_closed_items = user_max_items_adjusted - most_visited_items;
  if (recently_closed_pages.size() < recently_closed_items) {
    most_visited_items += recently_closed_items - recently_closed_pages.size();
    recently_closed_items = recently_closed_pages.size();
  }

  if (most_visited_pages_have_updates) {
    // Delete the content in JumpListIconsMostVisited folder and log the results
    // to UMA.
    base::FilePath icon_dir_most_visited = icon_dir.DirName().Append(
        icon_dir.BaseName().value() + FILE_PATH_LITERAL("MostVisited"));

    DeleteDirectoryContentAndLogResults(icon_dir_most_visited,
                                        kFileDeleteLimit);

    // If the directory doesn't exist (we have tried to create it in
    // DeleteDirectoryContentAndLogResults) or is not empty, skip updating the
    // jumplist icons. The jumplist links should be updated anyway, as it
    // doesn't involve disk IO. In this case, Chrome's icon will be used for the
    // new links.
    if (base::DirectoryExists(icon_dir_most_visited) &&
        base::IsDirectoryEmpty(icon_dir_most_visited)) {
      // Create icon files for shortcuts in the "Most Visited" category.
      CreateIconFiles(icon_dir_most_visited, most_visited_pages,
                      most_visited_items);
    }
  }

  if (recently_closed_pages_have_updates) {
    // Delete the content in JumpListIconsRecentClosed folder and log the
    // results to UMA.
    base::FilePath icon_dir_recent_closed = icon_dir.DirName().Append(
        icon_dir.BaseName().value() + FILE_PATH_LITERAL("RecentClosed"));

    DeleteDirectoryContentAndLogResults(icon_dir_recent_closed,
                                        kFileDeleteLimit);

    if (base::DirectoryExists(icon_dir_recent_closed) &&
        base::IsDirectoryEmpty(icon_dir_recent_closed)) {
      // Create icon files for shortcuts in the "Recently Closed" category.
      CreateIconFiles(icon_dir_recent_closed, recently_closed_pages,
                      recently_closed_items);
    }
  }

  // TODO(chengx): Remove the UMA histogram after fixing http://crbug.com/40407.
  SCOPED_UMA_HISTOGRAM_TIMER("WinJumplist.UpdateJumpListDuration");

  // Update the "Most Visited" category of the JumpList if it exists.
  // This update request is applied into the JumpList when we commit this
  // transaction.
  if (!jumplist_updater.AddCustomCategory(
          l10n_util::GetStringUTF16(IDS_NEW_TAB_MOST_VISITED),
          most_visited_pages, most_visited_items)) {
    return false;
  }

  // Update the "Recently Closed" category of the JumpList.
  if (!jumplist_updater.AddCustomCategory(
          l10n_util::GetStringUTF16(IDS_RECENTLY_CLOSED),
          recently_closed_pages, recently_closed_items)) {
    return false;
  }

  // Update the "Tasks" category of the JumpList.
  if (!UpdateTaskCategory(&jumplist_updater, incognito_availability))
    return false;

  // Commit this transaction and send the updated JumpList to Windows.
  return jumplist_updater.CommitUpdate();
}

// Updates the jumplist, once all the data has been fetched.
void RunUpdateJumpList(IncognitoModePrefs::Availability incognito_availability,
                       const std::wstring& app_id,
                       const base::FilePath& icon_dir,
                       base::RefCountedData<JumpListData>* ref_counted_data) {
  JumpListData* data = &ref_counted_data->data;
  ShellLinkItemList local_most_visited_pages;
  ShellLinkItemList local_recently_closed_pages;
  bool most_visited_pages_have_updates;
  bool recently_closed_pages_have_updates;

  {
    base::AutoLock auto_lock(data->list_lock_);
    // Make sure we are not out of date: if icon_urls_ is not empty, then
    // another notification has been received since we processed this one
    if (!data->icon_urls_.empty())
      return;

    // Make local copies of lists and flags so we can release the lock.
    local_most_visited_pages = data->most_visited_pages_;
    local_recently_closed_pages = data->recently_closed_pages_;

    most_visited_pages_have_updates = data->most_visited_pages_have_updates_;
    recently_closed_pages_have_updates =
        data->recently_closed_pages_have_updates_;

    // Clear the flags to reflect that we'll take actions on these updates.
    data->most_visited_pages_have_updates_ = false;
    data->recently_closed_pages_have_updates_ = false;
  }

  if (!most_visited_pages_have_updates && !recently_closed_pages_have_updates)
    return;

  // Updates the application JumpList. If it fails, reset the flags to true if
  // they were so that the corresponding JumpList categories will be tried to
  // update again in the next run.
  if (!UpdateJumpList(
          app_id.c_str(), icon_dir, local_most_visited_pages,
          local_recently_closed_pages, most_visited_pages_have_updates,
          recently_closed_pages_have_updates, incognito_availability)) {
    base::AutoLock auto_lock(data->list_lock_);
    if (most_visited_pages_have_updates)
      data->most_visited_pages_have_updates_ = true;
    if (recently_closed_pages_have_updates)
      data->recently_closed_pages_have_updates_ = true;
  }
}

}  // namespace

JumpList::JumpListData::JumpListData() {}

JumpList::JumpListData::~JumpListData() {}

JumpList::JumpList(Profile* profile)
    : RefcountedKeyedService(content::BrowserThread::GetTaskRunnerForThread(
          content::BrowserThread::UI)),
      profile_(profile),
      jumplist_data_(new base::RefCountedData<JumpListData>),
      task_id_(base::CancelableTaskTracker::kBadTaskId),
      update_jumplist_task_runner_(base::CreateCOMSTATaskRunnerWithTraits(
          base::TaskTraits()
              .WithPriority(base::TaskPriority::USER_VISIBLE)
              .WithShutdownBehavior(
                  base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN)
              .MayBlock())),
      delete_jumplisticons_task_runner_(
          base::CreateSequencedTaskRunnerWithTraits(
              base::TaskTraits()
                  .WithPriority(base::TaskPriority::BACKGROUND)
                  .WithShutdownBehavior(
                      base::TaskShutdownBehavior::CONTINUE_ON_SHUTDOWN)
                  .MayBlock())),
      weak_ptr_factory_(this) {
  DCHECK(Enabled());
  // To update JumpList when a tab is added or removed, we add this object to
  // the observer list of the TabRestoreService class.
  // When we add this object to the observer list, we save the pointer to this
  // TabRestoreService object. This pointer is used when we remove this object
  // from the observer list.
  sessions::TabRestoreService* tab_restore_service =
      TabRestoreServiceFactory::GetForProfile(profile_);
  if (!tab_restore_service)
    return;

  app_id_ =
      shell_integration::win::GetChromiumModelIdForProfile(profile_->GetPath());
  icon_dir_ = profile_->GetPath().Append(chrome::kJumpListIconDirname);

  scoped_refptr<history::TopSites> top_sites =
      TopSitesFactory::GetForProfile(profile_);
  if (top_sites) {
    // TopSites updates itself after a delay. This is especially noticable when
    // your profile is empty. Ask TopSites to update itself when jumplist is
    // initialized.
    top_sites->SyncWithHistory();
    // Register as TopSitesObserver so that we can update ourselves when the
    // TopSites changes.
    top_sites->AddObserver(this);
  }
  tab_restore_service->AddObserver(this);
  pref_change_registrar_.reset(new PrefChangeRegistrar);
  pref_change_registrar_->Init(profile_->GetPrefs());
  pref_change_registrar_->Add(
      prefs::kIncognitoModeAvailability,
      base::Bind(&JumpList::OnIncognitoAvailabilityChanged, this));
}

JumpList::~JumpList() {
  DCHECK(CalledOnValidThread());
  Terminate();
}

// static
bool JumpList::Enabled() {
  return JumpListUpdater::IsEnabled();
}

void JumpList::CancelPendingUpdate() {
  DCHECK(CalledOnValidThread());
  if (task_id_ != base::CancelableTaskTracker::kBadTaskId) {
    cancelable_task_tracker_.TryCancel(task_id_);
    task_id_ = base::CancelableTaskTracker::kBadTaskId;
  }
}

void JumpList::Terminate() {
  DCHECK(CalledOnValidThread());
  CancelPendingUpdate();
  if (profile_) {
    sessions::TabRestoreService* tab_restore_service =
        TabRestoreServiceFactory::GetForProfile(profile_);
    if (tab_restore_service)
      tab_restore_service->RemoveObserver(this);
    scoped_refptr<history::TopSites> top_sites =
        TopSitesFactory::GetForProfile(profile_);
    if (top_sites)
      top_sites->RemoveObserver(this);
    pref_change_registrar_.reset();
  }
  profile_ = NULL;
}

void JumpList::ShutdownOnUIThread() {
  DCHECK(CalledOnValidThread());
  Terminate();
}

void JumpList::OnMostVisitedURLsAvailable(
    const history::MostVisitedURLList& urls) {
  DCHECK(CalledOnValidThread());
  // If we have a pending favicon request, cancel it here (it is out of date).
  CancelPendingUpdate();

  {
    JumpListData* data = &jumplist_data_->data;
    base::AutoLock auto_lock(data->list_lock_);
    data->most_visited_pages_.clear();
    for (size_t i = 0; i < urls.size(); i++) {
      const history::MostVisitedURL& url = urls[i];
      scoped_refptr<ShellLinkItem> link = CreateShellLink();
      std::string url_string = url.url.spec();
      std::wstring url_string_wide = base::UTF8ToWide(url_string);
      link->GetCommandLine()->AppendArgNative(url_string_wide);
      link->GetCommandLine()->AppendSwitchASCII(
          switches::kWinJumplistAction, jumplist::kMostVisitedCategory);
      link->set_title(!url.title.empty() ? url.title : url_string_wide);
      data->most_visited_pages_.push_back(link);
      data->icon_urls_.push_back(std::make_pair(url_string, link));
    }
    data->most_visited_pages_have_updates_ = true;
  }

  // Send a query that retrieves the first favicon.
  StartLoadingFavicon();
}

void JumpList::TabRestoreServiceChanged(sessions::TabRestoreService* service) {
  DCHECK(CalledOnValidThread());
  // if we have a pending favicon request, cancel it here (it is out of date).
  CancelPendingUpdate();

  // Create a list of ShellLinkItems from the "Recently Closed" pages.
  // As noted above, we create a ShellLinkItem objects with the following
  // parameters.
  // * arguments
  //   The last URL of the tab object.
  // * title
  //   The title of the last URL.
  // * icon
  //   An empty string. This value is to be updated in OnFaviconDataAvailable().
  // This code is copied from
  // RecentlyClosedTabsHandler::TabRestoreServiceChanged() to emulate it.
  const int kRecentlyClosedCount = 3;
  sessions::TabRestoreService* tab_restore_service =
      TabRestoreServiceFactory::GetForProfile(profile_);

  {
    JumpListData* data = &jumplist_data_->data;
    base::AutoLock auto_lock(data->list_lock_);
    data->recently_closed_pages_.clear();

    for (const auto& entry : tab_restore_service->entries()) {
      switch (entry->type) {
        case sessions::TabRestoreService::TAB:
          AddTab(static_cast<const sessions::TabRestoreService::Tab&>(*entry),
                 kRecentlyClosedCount, data);
          break;
        case sessions::TabRestoreService::WINDOW:
          AddWindow(
              static_cast<const sessions::TabRestoreService::Window&>(*entry),
              kRecentlyClosedCount, data);
          break;
      }
    }

    data->recently_closed_pages_have_updates_ = true;
  }

  // Send a query that retrieves the first favicon.
  StartLoadingFavicon();
}

void JumpList::TabRestoreServiceDestroyed(
    sessions::TabRestoreService* service) {}

bool JumpList::AddTab(const sessions::TabRestoreService::Tab& tab,
                      size_t max_items,
                      JumpListData* data) {
  DCHECK(CalledOnValidThread());
  data->list_lock_.AssertAcquired();

  // This code adds the URL and the title strings of the given tab to |data|.
  if (data->recently_closed_pages_.size() >= max_items)
    return false;

  scoped_refptr<ShellLinkItem> link = CreateShellLink();
  const sessions::SerializedNavigationEntry& current_navigation =
      tab.navigations.at(tab.current_navigation_index);
  std::string url = current_navigation.virtual_url().spec();
  link->GetCommandLine()->AppendArgNative(base::UTF8ToWide(url));
  link->GetCommandLine()->AppendSwitchASCII(switches::kWinJumplistAction,
                                            jumplist::kRecentlyClosedCategory);
  link->set_title(current_navigation.title());
  data->recently_closed_pages_.push_back(link);
  data->icon_urls_.push_back(std::make_pair(std::move(url), std::move(link)));

  return true;
}

void JumpList::AddWindow(const sessions::TabRestoreService::Window& window,
                         size_t max_items,
                         JumpListData* data) {
  DCHECK(CalledOnValidThread());
  data->list_lock_.AssertAcquired();

  // This code enumerates all the tabs in the given window object and add their
  // URLs and titles to |data|.
  DCHECK(!window.tabs.empty());

  for (const auto& tab : window.tabs) {
    if (!AddTab(*tab, max_items, data))
      return;
  }
}

void JumpList::StartLoadingFavicon() {
  DCHECK(CalledOnValidThread());

  GURL url;
  bool waiting_for_icons = true;
  {
    JumpListData* data = &jumplist_data_->data;
    base::AutoLock auto_lock(data->list_lock_);
    waiting_for_icons = !data->icon_urls_.empty();
    if (waiting_for_icons) {
      // Ask FaviconService if it has a favicon of a URL.
      // When FaviconService has one, it will call OnFaviconDataAvailable().
      url = GURL(data->icon_urls_.front().first);
    }
  }

  if (!waiting_for_icons) {
    // No more favicons are needed by the application JumpList. Schedule a
    // RunUpdateJumpList call.
    PostRunUpdate();
    return;
  }

  favicon::FaviconService* favicon_service =
      FaviconServiceFactory::GetForProfile(profile_,
                                           ServiceAccessType::EXPLICIT_ACCESS);
  task_id_ = favicon_service->GetFaviconImageForPageURL(
      url,
      base::Bind(&JumpList::OnFaviconDataAvailable, base::Unretained(this)),
      &cancelable_task_tracker_);
}

void JumpList::OnFaviconDataAvailable(
    const favicon_base::FaviconImageResult& image_result) {
  DCHECK(CalledOnValidThread());

  // If there is currently a favicon request in progress, it is now outdated,
  // as we have received another, so nullify the handle from the old request.
  task_id_ = base::CancelableTaskTracker::kBadTaskId;
  // Lock the list to set icon data and pop the url.
  {
    JumpListData* data = &jumplist_data_->data;
    base::AutoLock auto_lock(data->list_lock_);
    // Attach the received data to the ShellLinkItem object.
    // This data will be decoded by the RunUpdateJumpList
    // method.
    if (!image_result.image.IsEmpty() && !data->icon_urls_.empty() &&
        data->icon_urls_.front().second.get()) {
      gfx::ImageSkia image_skia = image_result.image.AsImageSkia();
      image_skia.EnsureRepsForSupportedScales();
      std::unique_ptr<gfx::ImageSkia> deep_copy(image_skia.DeepCopy());
      data->icon_urls_.front().second->set_icon_image(*deep_copy);
    }

    if (!data->icon_urls_.empty())
      data->icon_urls_.pop_front();
  }
  // Check whether we need to load more favicons.
  StartLoadingFavicon();
}

void JumpList::OnIncognitoAvailabilityChanged() {
  DCHECK(CalledOnValidThread());

  bool waiting_for_icons = true;
  {
    JumpListData* data = &jumplist_data_->data;
    base::AutoLock auto_lock(data->list_lock_);
    waiting_for_icons = !data->icon_urls_.empty();
  }

  // Since neither the "Most Visited" category nor the "Recently Closed"
  // category changes, mark the flags so that icon files for those categories
  // won't be updated later on.
  if (!waiting_for_icons)
    PostRunUpdate();
}

void JumpList::PostRunUpdate() {
  DCHECK(CalledOnValidThread());

  TRACE_EVENT0("browser", "JumpList::PostRunUpdate");
  // Initialize the one-shot timer to update the jumplists in a while.
  // If there is already a request queued then cancel it and post the new
  // request. This ensures that JumpListUpdates won't happen until there has
  // been a brief quiet period, thus avoiding update storms.
  if (timer_.IsRunning()) {
    timer_.Reset();
  } else {
    timer_.Start(FROM_HERE, kDelayForJumplistUpdate, this,
                 &JumpList::DeferredRunUpdate);
  }
}

void JumpList::DeferredRunUpdate() {
  DCHECK(CalledOnValidThread());

  TRACE_EVENT0("browser", "JumpList::DeferredRunUpdate");
  // Check if incognito windows (or normal windows) are disabled by policy.
  IncognitoModePrefs::Availability incognito_availability =
      profile_ ? IncognitoModePrefs::GetAvailability(profile_->GetPrefs())
               : IncognitoModePrefs::ENABLED;

  // Post a task to update the JumpList, which consists of 1) delete old icons,
  // 2) create new icons, 3) notify the OS.
  update_jumplist_task_runner_->PostTask(
      FROM_HERE, base::Bind(&RunUpdateJumpList, incognito_availability, app_id_,
                            icon_dir_, base::RetainedRef(jumplist_data_)));

  // Post a task to delete JumpListIcons folder as it's no longer needed.
  // Now we have JumpListIconsMostVisited folder and JumpListIconsRecentClosed
  // folder instead.
  delete_jumplisticons_task_runner_->PostTask(
      FROM_HERE,
      base::Bind(&DeleteDirectoryAndLogResults, icon_dir_, kFileDeleteLimit));

  // Post a task to delete JumpListIconsOld folder as it's no longer needed.
  base::FilePath icon_dir_old = icon_dir_.DirName().Append(
      icon_dir_.BaseName().value() + FILE_PATH_LITERAL("Old"));

  delete_jumplisticons_task_runner_->PostTask(
      FROM_HERE, base::Bind(&DeleteDirectoryAndLogResults,
                            std::move(icon_dir_old), kFileDeleteLimit));
}

void JumpList::TopSitesLoaded(history::TopSites* top_sites) {
}

void JumpList::TopSitesChanged(history::TopSites* top_sites,
                               ChangeReason change_reason) {
  top_sites->GetMostVisitedURLs(
      base::Bind(&JumpList::OnMostVisitedURLsAvailable,
                 weak_ptr_factory_.GetWeakPtr()),
      false);
}