Move download filename determintion into a separate class.

chrome/browser/download/chrome_download_manager_delegate.cc

 // Copyright (c) 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/download/chrome_download_manager_delegate.h"
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/callback.h"
 #include "base/file_util.h"
 #include "base/prefs/pref_member.h"
 #include "base/prefs/pref_service.h"
 #include "base/rand_util.h"
 #include "base/stringprintf.h"
 #include "base/time.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/download/download_completion_blocker.h"
 #include "chrome/browser/download/download_crx_util.h"
-#include "chrome/browser/download/download_extensions.h"
 #include "chrome/browser/download/download_file_picker.h"
 #include "chrome/browser/download/download_history.h"
 #include "chrome/browser/download/download_path_reservation_tracker.h"
 #include "chrome/browser/download/download_prefs.h"
 #include "chrome/browser/download/download_service.h"
 #include "chrome/browser/download/download_service_factory.h"
-#include "chrome/browser/download/download_status_updater.h"
+#include "chrome/browser/download/download_target_determiner.h"
 #include "chrome/browser/download/download_util.h"
 #include "chrome/browser/download/save_package_file_picker.h"
-#include "chrome/browser/extensions/api/downloads/downloads_api.h"
 #include "chrome/browser/extensions/crx_installer.h"
-#include "chrome/browser/extensions/extension_service.h"
-#include "chrome/browser/extensions/extension_system.h"
-#include "chrome/browser/history/history_service.h"
-#include "chrome/browser/history/history_service_factory.h"
 #include "chrome/browser/platform_util.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/safe_browsing/safe_browsing_service.h"
-#include "chrome/browser/ui/host_desktop.h"
-#include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "chrome/common/chrome_notification_types.h"
-#include "chrome/common/extensions/feature_switch.h"
-#include "chrome/common/extensions/user_script.h"
+#include "chrome/common/extensions/extension.h"
 #include "chrome/common/pref_names.h"
 #include "components/user_prefs/pref_registry_syncable.h"
 #include "content/public/browser/download_item.h"
 #include "content/public/browser/download_manager.h"
 #include "content/public/browser/notification_source.h"
-#include "content/public/browser/web_contents.h"
-#include "content/public/browser/web_contents_delegate.h"
-#include "grit/generated_resources.h"
-#include "net/base/net_util.h"
-#include "ui/base/l10n/l10n_util.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/drive/drive_download_handler.h"
 #include "chrome/browser/chromeos/drive/drive_file_system_util.h"
-#include "chrome/browser/download/download_file_picker_chromeos.h"
 #include "chrome/browser/download/save_package_file_picker_chromeos.h"
 #endif
 
 using content::BrowserContext;
 using content::BrowserThread;
 using content::DownloadId;
 using content::DownloadItem;
 using content::DownloadManager;
-using content::WebContents;
 using safe_browsing::DownloadProtectionService;
 
 namespace {
 
 // String pointer used for identifying safebrowing data associated with
 // a download item.
 static const char safe_browsing_id[] = "Safe Browsing ID";
 
 // The state of a safebrowsing check.
 class SafeBrowsingState : public DownloadCompletionBlocker {
@@ skipping 16 matching lines @@
   }
 
  private:
   DownloadProtectionService::DownloadCheckResult verdict_;
 
   DISALLOW_COPY_AND_ASSIGN(SafeBrowsingState);
 };
 
 SafeBrowsingState::~SafeBrowsingState() {}
 
-// Generate a filename based on the response from the server.  Similar
-// in operation to net::GenerateFileName(), but uses a localized
-// default name.
-void GenerateFileNameFromRequest(const DownloadItem& download_item,
-                                 base::FilePath* generated_name,
-                                 std::string referrer_charset) {
-  std::string default_file_name(
-      l10n_util::GetStringUTF8(IDS_DEFAULT_DOWNLOAD_FILENAME));
-
-  *generated_name = net::GenerateFileName(download_item.GetURL(),
-                                          download_item.GetContentDisposition(),
-                                          referrer_charset,
-                                          download_item.GetSuggestedFilename(),
-                                          download_item.GetMimeType(),
-                                          default_file_name);
-}
-
-typedef base::Callback<void(bool)> VisitedBeforeCallback;
-
-// Condenses the results from HistoryService::GetVisibleVisitCountToHost() to a
-// single bool so that VisitedBeforeCallback can curry up to 5 other parameters
-// without a struct.
-void VisitCountsToVisitedBefore(
-    const VisitedBeforeCallback& callback,
-    HistoryService::Handle unused_handle,
-    bool found_visits,
-    int count,
-    base::Time first_visit) {
-  callback.Run(found_visits && count &&
-      (first_visit.LocalMidnight() < base::Time::Now().LocalMidnight()));
-}
-
-base::FilePath GetIntermediatePath(const base::FilePath& target_path,
-                                   content::DownloadDangerType danger_type,
-                                   bool is_forced_path) {
-  // If the download is not dangerous, just append .crdownload to the target
-  // path.
-  if (danger_type == content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS) {
-    if (is_forced_path)
-      return target_path;
-    return download_util::GetCrDownloadPath(target_path);
-  }
-
-  // If the download is potentially dangerous we create a filename of the form
-  // 'Unconfirmed <random>.crdownload'.
-  base::FilePath::StringType file_name;
-  base::FilePath dir = target_path.DirName();
-#if defined(OS_WIN)
-  string16 unconfirmed_prefix =
-      l10n_util::GetStringUTF16(IDS_DOWNLOAD_UNCONFIRMED_PREFIX);
-#else
-  std::string unconfirmed_prefix =
-      l10n_util::GetStringUTF8(IDS_DOWNLOAD_UNCONFIRMED_PREFIX);
-#endif
-  base::SStringPrintf(
-      &file_name,
-      unconfirmed_prefix.append(
-          FILE_PATH_LITERAL(" %d.crdownload")).c_str(),
-      base::RandInt(0, 1000000));
-  return dir.Append(file_name);
-}
-
 // Returns a file path in the form that is expected by
 // platform_util::OpenItem/ShowItemInFolder, including any transformation
 // required for download abstractions layered on top of the core system,
 // e.g. download to Drive.
 base::FilePath GetPlatformDownloadPath(Profile* profile,
                                        const DownloadItem* download) {
 #if defined(OS_CHROMEOS)
   drive::DriveDownloadHandler* drive_download_handler =
       drive::DriveDownloadHandler::GetForProfile(profile);
   if (drive_download_handler &&
@@ skipping 36 matching lines @@
   if (!profile_->IsOffTheRecord())
     return DownloadId(this, next_download_id_++);
 
   return BrowserContext::GetDownloadManager(profile_->GetOriginalProfile())->
       GetDelegate()->GetNextId();
 }
 
 bool ChromeDownloadManagerDelegate::DetermineDownloadTarget(
     DownloadItem* download,
     const content::DownloadTargetCallback& callback) {
-#if defined(FULL_SAFE_BROWSING)
-  DownloadProtectionService* service = GetDownloadProtectionService();
-  if (service) {
-    VLOG(2) << __FUNCTION__ << "() Start SB URL check for download = "
-            << download->DebugString(false);
-    service->CheckDownloadUrl(
-        *download,
-        base::Bind(
-            &ChromeDownloadManagerDelegate::CheckDownloadUrlDone,
-            this,
-            download->GetId(),
-            callback));
-    return true;
-  }
-#endif
-  CheckDownloadUrlDone(download->GetId(), callback,
-                       DownloadProtectionService::SAFE);
+  DownloadTargetDeterminer::CompletionCallback destination_callback =
+      base::Bind(&ChromeDownloadManagerDelegate::OnDetermineDownloadTargetDone,
+                 this, callback);
+  DownloadTargetDeterminer::Start(download,
+                                  download_prefs_.get(),
+                                  last_download_path_,
+                                  this,
+                                  destination_callback);
   return true;
 }
 
-void ChromeDownloadManagerDelegate::ChooseDownloadPath(
-    DownloadItem* item,
-    const base::FilePath& suggested_path,
-    const FileSelectedCallback& file_selected_callback) {
-  // Deletes itself.
-  DownloadFilePicker* file_picker =
-#if defined(OS_CHROMEOS)
-      new DownloadFilePickerChromeOS();
-#else
-      new DownloadFilePicker();
-#endif
-  file_picker->Init(download_manager_, item, suggested_path,
-                    file_selected_callback);
-}
-
 bool ChromeDownloadManagerDelegate::ShouldOpenFileBasedOnExtension(
     const base::FilePath& path) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  base::FilePath::StringType extension = path.Extension();
-  if (extension.empty())
+  if (path.Extension().empty())
     return false;
+  // TODO(asanka): This determination is done based on |path|, while elsewhere

[benjhayden, 2013/04/09 15:46:32]

Where else?

[asanka, 2013/04/16 20:34:01]

Updated comment.

+  // an extension download is recognized based on characteristics of the
+  // DownloadItem other than the path. Reconcile this.
   if (extensions::Extension::IsExtension(path))
     return false;
-  DCHECK(extension[0] == base::FilePath::kExtensionSeparator);
-  extension.erase(0, 1);
-  return download_prefs_->IsAutoOpenEnabledForExtension(extension);
+  return download_prefs_->IsAutoOpenEnabledBasedOnExtension(path);
 }
 
 // static
 void ChromeDownloadManagerDelegate::DisableSafeBrowsing(DownloadItem* item) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 #if defined(FULL_SAFE_BROWSING)
   SafeBrowsingState* state = static_cast<SafeBrowsingState*>(
       item->GetUserData(&safe_browsing_id));
   if (!state) {
     state = new SafeBrowsingState();
@@ skipping 114 matching lines @@
 
   *download_save_dir = prefs->GetFilePath(prefs::kDownloadDefaultDirectory);
 
   *skip_dir_check = false;
 #if defined(OS_CHROMEOS)
   *skip_dir_check = drive::util::IsUnderDriveMountPoint(*website_save_dir);
 #endif
 }
 
 void ChromeDownloadManagerDelegate::ChooseSavePath(
-    WebContents* web_contents,
+    content::WebContents* web_contents,
     const base::FilePath& suggested_path,
     const base::FilePath::StringType& default_extension,
     bool can_save_as_complete,
     const content::SavePackagePathPickedCallback& callback) {
   // Deletes itself.
 #if defined(OS_CHROMEOS)
   new SavePackageFilePickerChromeOS(
       web_contents,
       suggested_path,
       can_save_as_complete,
@@ skipping 35 matching lines @@
                                                        download->GetFullPath()),
                                             callback);
 }
 
 void ChromeDownloadManagerDelegate::ClearLastDownloadPath() {
   last_download_path_.clear();
 }
 
 DownloadProtectionService*
     ChromeDownloadManagerDelegate::GetDownloadProtectionService() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 #if defined(FULL_SAFE_BROWSING)
   SafeBrowsingService* sb_service = g_browser_process->safe_browsing_service();
   if (sb_service && sb_service->download_protection_service() &&
       profile_->GetPrefs()->GetBoolean(prefs::kSafeBrowsingEnabled)) {
     return sb_service->download_protection_service();
   }
 #endif
   return NULL;
 }
 
-// TODO(phajdan.jr): This is apparently not being exercised in tests.
-bool ChromeDownloadManagerDelegate::IsDangerousFile(
-    const DownloadItem& download,
+void ChromeDownloadManagerDelegate::PromptUserForDownloadPath(
+    DownloadItem* download,
     const base::FilePath& suggested_path,
-    bool visited_referrer_before) {
+    const DownloadTargetDeterminerDelegate::FileSelectedCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  const bool is_extension_download =
-      download_crx_util::IsExtensionDownload(download);
-
-  // User-initiated extension downloads from pref-whitelisted sources are not
-  // considered dangerous.
-  if (download.HasUserGesture() &&
-      is_extension_download &&
-      download_crx_util::OffStoreInstallAllowedByPrefs(profile_, download)) {
-    return false;
-  }
-
-  // Extensions that are not from the gallery are considered dangerous.
-  // When off-store install is disabled we skip this, since in this case, we
-  // will not offer to install the extension.
-  if (extensions::FeatureSwitch::easy_off_store_install()->IsEnabled() &&
-      is_extension_download &&
-      !extensions::WebstoreInstaller::GetAssociatedApproval(download)) {
-    return true;
-  }
-
-  // Anything the user has marked auto-open is OK if it's user-initiated.
-  if (ShouldOpenFileBasedOnExtension(suggested_path) &&
-      download.HasUserGesture())
-    return false;
-
-  // "Allow on user gesture" is OK when we have a user gesture and the hosting
-  // page has been visited before today.
-  download_util::DownloadDangerLevel danger_level =
-      download_util::GetFileDangerLevel(suggested_path.BaseName());
-  if (danger_level == download_util::AllowOnUserGesture) {
-    if (download.GetTransitionType() &
-            content::PAGE_TRANSITION_FROM_ADDRESS_BAR) {
-      return false;
-    }
-    return !download.HasUserGesture() || !visited_referrer_before;
-  }
-
-  return danger_level == download_util::Dangerous;
+  DownloadFilePicker::ShowFilePicker(
+      download,
+      suggested_path,
+      base::Bind(&ChromeDownloadManagerDelegate::OnDownloadPathSelected,
+                 this,
+                 callback));
 }
 
-void ChromeDownloadManagerDelegate::GetReservedPath(
-    DownloadItem& download,
-    const base::FilePath& target_path,
-    const base::FilePath& default_download_path,
-    bool should_uniquify_path,
-    const DownloadPathReservationTracker::ReservedPathCallback& callback) {
-  DownloadPathReservationTracker::GetReservedPath(
-      download, target_path, default_download_path, should_uniquify_path,
-      callback);
+ExtensionDownloadsEventRouter*
+    ChromeDownloadManagerDelegate::GetExtensionEventRouter() {
+  return DownloadServiceFactory::GetForProfile(profile_)->
+      GetExtensionEventRouter();
 }
 
-void ChromeDownloadManagerDelegate::CheckDownloadUrlDone(
-    int32 download_id,
-    const content::DownloadTargetCallback& callback,
-    DownloadProtectionService::DownloadCheckResult result) {
+void ChromeDownloadManagerDelegate::DetermineLocalPath(
+    DownloadItem* download,
+    const base::FilePath& virtual_path,
+    const DownloadTargetDeterminerDelegate::LocalPathCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DownloadItem* download = download_manager_->GetDownload(download_id);
-  if (!download || (download->GetState() != DownloadItem::IN_PROGRESS))
-    return;
-
-  VLOG(2) << __FUNCTION__ << "() download = " << download->DebugString(false)
-          << " verdict = " << result;
-  content::DownloadDangerType danger_type = download->GetDangerType();
-  if (result != DownloadProtectionService::SAFE)
-    danger_type = content::DOWNLOAD_DANGER_TYPE_DANGEROUS_URL;
-
-  // HistoryServiceFactory redirects incognito profiles to on-record profiles.
-  HistoryService* history = HistoryServiceFactory::GetForProfile(
-      profile_, Profile::EXPLICIT_ACCESS);
-  if (!history || !download->GetReferrerUrl().is_valid()) {
-    // If the original profile doesn't have a HistoryService or the referrer url
-    // is invalid, then give up and assume the referrer has not been visited
-    // before. There's no history for on-record profiles in unit_tests, for
-    // example.
-    CheckVisitedReferrerBeforeDone(download_id, callback, danger_type, false);
+#if defined(OS_CHROMEOS)
+  drive::DriveDownloadHandler* drive_download_handler =
+      drive::DriveDownloadHandler::GetForProfile(GetProfile());
+  if (drive_download_handler) {
+    drive_download_handler->SubstituteDriveDownloadPath(
+        virtual_path_, download_,
+        base::Bind(
+            &DownloadTargetDeterminer::DetermineLocalPathDone,
+            weak_ptr_factory_.GetWeakPtr()));
     return;
   }
-  history->GetVisibleVisitCountToHost(
-      download->GetReferrerUrl(), &history_consumer_,
-      base::Bind(&VisitCountsToVisitedBefore, base::Bind(
-          &ChromeDownloadManagerDelegate::CheckVisitedReferrerBeforeDone,
-          this, download_id, callback, danger_type)));
+#endif
+  callback.Run(virtual_path);
+}
+
+void ChromeDownloadManagerDelegate::ReserveVirtualPath(
+    content::DownloadItem* download,
+    const base::FilePath& virtual_path,
+    bool should_uniquify_path,
+    const DownloadTargetDeterminerDelegate::ReservedPathCallback& callback) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!virtual_path.empty());
+#if defined(OS_CHROMEOS)
+  // TODO(asanka): Handle path reservations for virtual paths as well.
+  //               http://crbug.com/151618
+  if (drive::util::IsUnderDriveMountPoint(virtual_path)) {
+    callback.Run(virtual_path, true);
+    return;
+  }
+#endif
+  DownloadPathReservationTracker::GetReservedPath(
+      *download, virtual_path, download_prefs_->DownloadPath(),
+      should_uniquify_path, callback);
+}
+
+void ChromeDownloadManagerDelegate::OnDownloadPathSelected(
+    const DownloadTargetDeterminerDelegate::FileSelectedCallback& callback,
+    const base::FilePath& virtual_path,
+    const base::FilePath& local_path) {
+  if (!virtual_path.empty())
+    last_download_path_ = virtual_path.DirName();
+  callback.Run(virtual_path, local_path);
+}
+
+void ChromeDownloadManagerDelegate::OnDetermineDownloadTargetDone(
+    const content::DownloadTargetCallback& callback,
+    const base::FilePath& virtual_path,

[benjhayden, 2013/04/09 15:46:32]

I spent a few seconds looking for where this was used.
s/virtual_path/unused_virtual_path/ ?

+    const base::FilePath& local_path,
+    const base::FilePath& intermediate_path,
+    content::DownloadItem::TargetDisposition target_disposition,
+    content::DownloadDangerType danger_type) {
+  callback.Run(local_path, target_disposition, danger_type, intermediate_path);
 }
 
 void ChromeDownloadManagerDelegate::CheckClientDownloadDone(
     int32 download_id,
     DownloadProtectionService::DownloadCheckResult result) {
   DownloadItem* item = download_manager_->GetDownload(download_id);
   if (!item || (item->GetState() != DownloadItem::IN_PROGRESS))
     return;
 
   VLOG(2) << __FUNCTION__ << "() download = " << item->DebugString(false)
@@ skipping 37 matching lines @@
   registrar_.Remove(this,
                     chrome::NOTIFICATION_CRX_INSTALLER_DONE,
                     source);
 
   scoped_refptr<extensions::CrxInstaller> installer =
       content::Source<extensions::CrxInstaller>(source).ptr();
   content::DownloadOpenDelayedCallback callback = crx_installers_[installer];
   crx_installers_.erase(installer.get());
   callback.Run(installer->did_handle_successfully());
 }
-
-struct ChromeDownloadManagerDelegate::ContinueFilenameDeterminationInfo {
-  ContinueFilenameDeterminationInfo();
-  ~ContinueFilenameDeterminationInfo();
-
-  int32 download_id;
-  content::DownloadTargetCallback callback;
-  content::DownloadDangerType danger_type;
-  bool visited_referrer_before;
-  bool should_prompt;
-};
-
-ChromeDownloadManagerDelegate::ContinueFilenameDeterminationInfo::
-    ContinueFilenameDeterminationInfo() {}
-ChromeDownloadManagerDelegate::ContinueFilenameDeterminationInfo::
-    ~ContinueFilenameDeterminationInfo() {}
-
-void ChromeDownloadManagerDelegate::CheckVisitedReferrerBeforeDone(
-    int32 download_id,
-    const content::DownloadTargetCallback& callback,
-    content::DownloadDangerType danger_type,
-    bool visited_referrer_before) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-
-  DownloadItem* download =
-      download_manager_->GetDownload(download_id);
-  if (!download || (download->GetState() != DownloadItem::IN_PROGRESS))
-    return;
-
-  bool should_prompt = (download->GetTargetDisposition() ==
-                        DownloadItem::TARGET_DISPOSITION_PROMPT);
-  bool is_forced_path = !download->GetForcedFilePath().empty();
-  base::FilePath generated_name;
-  base::FilePath suggested_path;
-
-  // Check whether this download is for an extension install or not.
-  // Allow extensions to be explicitly saved.
-  if (!is_forced_path) {
-    GenerateFileNameFromRequest(
-        *download,
-        &generated_name,
-        profile_->GetPrefs()->GetString(prefs::kDefaultCharset));
-
-    // Freeze the user's preference for showing a Save As dialog.  We're going
-    // to bounce around a bunch of threads and we don't want to worry about race
-    // conditions where the user changes this pref out from under us.
-    if (download_prefs_->PromptForDownload()) {
-      // But ignore the user's preference for the following scenarios:
-      // 1) Extension installation. Note that we only care here about the case
-      //    where an extension is installed, not when one is downloaded with
-      //    "save as...".
-      // 2) Filetypes marked "always open." If the user just wants this file
-      //    opened, don't bother asking where to keep it.
-      if (!download_crx_util::IsExtensionDownload(*download) &&
-          !ShouldOpenFileBasedOnExtension(generated_name))
-        should_prompt = true;
-    }
-    if (download_prefs_->IsDownloadPathManaged())
-      should_prompt = false;
-
-    // Determine the proper path for a download, by either one of the following:
-    // 1) using the default download directory.
-    // 2) prompting the user.
-    base::FilePath target_directory;
-    if (should_prompt && !last_download_path_.empty())
-      target_directory = last_download_path_;
-    else
-      target_directory = download_prefs_->DownloadPath();
-    suggested_path = target_directory.Append(generated_name);
-  } else {
-    DCHECK(!should_prompt);
-    suggested_path = download->GetForcedFilePath();
-  }
-
-  ContinueFilenameDeterminationInfo continue_info;
-  continue_info.download_id = download_id;
-  continue_info.callback = callback;
-  continue_info.danger_type = danger_type;
-  continue_info.visited_referrer_before = visited_referrer_before;
-  continue_info.should_prompt = should_prompt;
-
-  base::Closure filename_determined = base::Bind(
-      &ChromeDownloadManagerDelegate::ContinueDeterminingFilename,
-      this, continue_info, suggested_path, is_forced_path);
-#if defined(OS_ANDROID)
-  filename_determined.Run();
-#else
-  if (is_forced_path ||
-      !DownloadServiceFactory::GetForProfile(profile_)
-        ->GetExtensionEventRouter()) {
-    filename_determined.Run();
-  } else {
-    DownloadService* service = DownloadServiceFactory::GetForProfile(profile_);
-    ExtensionDownloadsEventRouter* router = service->GetExtensionEventRouter();
-    ExtensionDownloadsEventRouter::FilenameChangedCallback overriding =
-      base::Bind(&ChromeDownloadManagerDelegate::OnExtensionOverridingFilename,
-                 this, continue_info);
-    router->OnDeterminingFilename(
-        download, generated_name, filename_determined, overriding);
-  }
-#endif
-}
-
-void ChromeDownloadManagerDelegate::OnExtensionOverridingFilename(
-    const ContinueFilenameDeterminationInfo& continue_info,
-    const base::FilePath& changed_filename,
-    bool overwrite) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DownloadItem* download =
-      download_manager_->GetDownload(continue_info.download_id);
-  if (!download || (download->GetState() != DownloadItem::IN_PROGRESS))
-    return;
-  // If an extension overrides the filename, then the target directory will be
-  // forced to download_prefs_->DownloadPath() since extensions cannot place
-  // downloaded files anywhere except there. This prevents subdirectories from
-  // accumulating: if an extension is allowed to say that a file should go in
-  // last_download_path/music/foo.mp3, then last_download_path will accumulate
-  // the subdirectory /music/ so that the next download may end up in
-  // Downloads/music/music/music/bar.mp3.
-  base::FilePath temp_filename(download_prefs_->DownloadPath().Append(
-      changed_filename).NormalizePathSeparators());
-  // Do not pass a mime type to GenerateSafeFileName so that it does not force
-  // the filename to have an extension if the (chrome) extension does not
-  // suggest it.
-  net::GenerateSafeFileName(std::string(), false, &temp_filename);
-  // If |is_forced_path| were true, then extensions would not have been
-  // consulted, so use |overwrite| instead of |is_forced_path|. This does NOT
-  // set DownloadItem::GetForcedFilePath()!
-  ContinueDeterminingFilename(continue_info, temp_filename, overwrite);
-}
-
-void ChromeDownloadManagerDelegate::ContinueDeterminingFilename(
-    const ContinueFilenameDeterminationInfo& continue_info,
-    const base::FilePath& suggested_path,
-    bool is_forced_path) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  int32 download_id = continue_info.download_id;
-  const content::DownloadTargetCallback& callback = continue_info.callback;
-  content::DownloadDangerType danger_type = continue_info.danger_type;
-  bool visited_referrer_before = continue_info.visited_referrer_before;
-  bool should_prompt = continue_info.should_prompt;
-  DownloadItem* download =
-      download_manager_->GetDownload(download_id);
-  if (!download || (download->GetState() != DownloadItem::IN_PROGRESS))
-    return;
-
-  // If the download hasn't already been marked dangerous (could be
-  // DANGEROUS_URL), check if it is a dangerous file.
-  if (danger_type == content::DOWNLOAD_DANGER_TYPE_NOT_DANGEROUS) {
-    if (!should_prompt && !is_forced_path &&
-        IsDangerousFile(*download, suggested_path, visited_referrer_before)) {
-      danger_type = content::DOWNLOAD_DANGER_TYPE_DANGEROUS_FILE;
-    }
-
-#if defined(FULL_SAFE_BROWSING)
-    DownloadProtectionService* service = GetDownloadProtectionService();
-    // If this type of files is handled by the enhanced SafeBrowsing download
-    // protection, mark it as potentially dangerous content until we are done
-    // with scanning it.
-    if (service && service->enabled()) {
-      // TODO(noelutz): if the user changes the extension name in the UI to
-      // something like .exe SafeBrowsing will currently *not* check if the
-      // download is malicious.
-      if (service->IsSupportedDownload(*download, suggested_path))
-        danger_type = content::DOWNLOAD_DANGER_TYPE_MAYBE_DANGEROUS_CONTENT;
-    }
-#endif
-  } else {
-    // Currently we only expect this case.
-    DCHECK_EQ(content::DOWNLOAD_DANGER_TYPE_DANGEROUS_URL, danger_type);
-  }
-
-#if defined (OS_CHROMEOS)
-  drive::DriveDownloadHandler* drive_download_handler =
-      drive::DriveDownloadHandler::GetForProfile(profile_);
-  if (drive_download_handler) {
-    drive_download_handler->SubstituteDriveDownloadPath(
-        suggested_path, download,
-        base::Bind(
-            &ChromeDownloadManagerDelegate::SubstituteDriveDownloadPathCallback,
-            this, download->GetId(), callback, should_prompt, is_forced_path,
-            danger_type));
-    return;
-  }
-#endif
-  GetReservedPath(
-      *download, suggested_path, download_prefs_->DownloadPath(),
-      !is_forced_path,
-      base::Bind(&ChromeDownloadManagerDelegate::OnPathReservationAvailable,
-                 this, download->GetId(), callback, should_prompt,
-                 danger_type));
-}
-
-#if defined (OS_CHROMEOS)
-// TODO(asanka): Merge this logic with the logic in DownloadFilePickerChromeOS.
-void ChromeDownloadManagerDelegate::SubstituteDriveDownloadPathCallback(
-    int32 download_id,
-    const content::DownloadTargetCallback& callback,
-    bool should_prompt,
-    bool is_forced_path,
-    content::DownloadDangerType danger_type,
-    const base::FilePath& suggested_path) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DownloadItem* download =
-      download_manager_->GetDownload(download_id);
-  if (!download || (download->GetState() != DownloadItem::IN_PROGRESS))
-    return;
-
-  if (suggested_path.empty()) {
-    // Substitution failed.
-    callback.Run(base::FilePath(),
-                 DownloadItem::TARGET_DISPOSITION_OVERWRITE,
-                 danger_type,
-                 base::FilePath());
-    return;
-  }
-
-  GetReservedPath(
-      *download, suggested_path, download_prefs_->DownloadPath(),
-      !is_forced_path,
-      base::Bind(&ChromeDownloadManagerDelegate::OnPathReservationAvailable,
-                 this, download->GetId(), callback, should_prompt,
-                 danger_type));
-}
-#endif
-
-void ChromeDownloadManagerDelegate::OnPathReservationAvailable(
-    int32 download_id,
-    const content::DownloadTargetCallback& callback,
-    bool should_prompt,
-    content::DownloadDangerType danger_type,
-    const base::FilePath& reserved_path,
-    bool reserved_path_verified) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  DownloadItem* download =
-      download_manager_->GetDownload(download_id);
-  if (!download || (download->GetState() != DownloadItem::IN_PROGRESS))
-    return;
-  if (should_prompt || !reserved_path_verified) {
-    // If the target path could not be verified then the path was non-existant,
-    // non writeable or could not be uniquified. Prompt the user.
-    ChooseDownloadPath(
-        download, reserved_path,
-        base::Bind(&ChromeDownloadManagerDelegate::OnTargetPathDetermined,
-                   this, download_id, callback,
-                   DownloadItem::TARGET_DISPOSITION_PROMPT, danger_type));
-  } else {
-    OnTargetPathDetermined(download_id, callback,
-                           DownloadItem::TARGET_DISPOSITION_OVERWRITE,
-                           danger_type, reserved_path);
-  }
-}
-
-void ChromeDownloadManagerDelegate::OnTargetPathDetermined(
-    int32 download_id,
-    const content::DownloadTargetCallback& callback,
-    DownloadItem::TargetDisposition disposition,
-    content::DownloadDangerType danger_type,
-    const base::FilePath& target_path) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  base::FilePath intermediate_path;
-  DownloadItem* download =
-      download_manager_->GetDownload(download_id);
-  if (!download || (download->GetState() != DownloadItem::IN_PROGRESS))
-    return;
-
-  // If |target_path| is empty, then that means that the user wants to cancel
-  // the download.
-  if (!target_path.empty()) {
-    intermediate_path = GetIntermediatePath(
-        target_path, danger_type, !download->GetForcedFilePath().empty());
-
-    // Retain the last directory. Exclude temporary downloads since the path
-    // likely points at the location of a temporary file.
-    // TODO(asanka): This logic is a hack. DownloadFilePicker should give us a
-    //               directory to persist. Or perhaps, if the Drive path
-    //               substitution logic is moved here, then we would have a
-    //               persistable path after the DownloadFilePicker is done.
-    if (disposition == DownloadItem::TARGET_DISPOSITION_PROMPT &&
-        !download->IsTemporary())
-      last_download_path_ = target_path.DirName();
-  }
-  callback.Run(target_path, disposition, danger_type, intermediate_path);
-}