Make a controller interface for media galleries dialogs.

chrome/browser/media_galleries/media_galleries_permission_controller.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/media_galleries/media_galleries_dialog_controller.h"
+#include "chrome/browser/media_galleries/media_galleries_permission_controller.h"
 
 #include "base/base_paths.h"
 #include "base/path_service.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/api/file_system/file_system_api.h"
 #include "chrome/browser/media_galleries/media_file_system_registry.h"
 #include "chrome/browser/media_galleries/media_galleries_histograms.h"
 #include "chrome/browser/media_galleries/media_gallery_context_menu.h"
@@ skipping 12 matching lines @@
 #include "ui/base/text/bytes_formatting.h"
 
 using extensions::APIPermission;
 using extensions::Extension;
 using storage_monitor::StorageInfo;
 using storage_monitor::StorageMonitor;
 
 namespace {
 
 // Comparator for sorting GalleryPermissionsVector -- sorts
-// allowed galleries low, and then sorts by absolute path.
+// selected galleries low, and then sorts by absolute path.
 bool GalleriesVectorComparator(
-    const MediaGalleriesDialogController::GalleryPermission& a,
-    const MediaGalleriesDialogController::GalleryPermission& b) {
-  if (a.allowed && !b.allowed)
+    const MediaGalleriesDialogController::Entry& a,
+    const MediaGalleriesDialogController::Entry& b) {
+  if (a.selected && !b.selected)
     return true;
-  if (!a.allowed && b.allowed)
+  if (!a.selected && b.selected)
     return false;
 
   return a.pref_info.AbsolutePath() < b.pref_info.AbsolutePath();
 }
 
 }  // namespace
 
-MediaGalleriesDialogController::MediaGalleriesDialogController(
+MediaGalleriesPermissionController::MediaGalleriesPermissionController(
     content::WebContents* web_contents,
     const Extension& extension,
     const base::Closure& on_finish)
       : web_contents_(web_contents),
         extension_(&extension),
         on_finish_(on_finish),
         preferences_(
             g_browser_process->media_file_system_registry()->GetPreferences(
                 GetProfile())),
         create_dialog_callback_(base::Bind(&MediaGalleriesDialog::Create)) {
   // Passing unretained pointer is safe, since the dialog controller
   // is self-deleting, and so won't be deleted until it can be shown
   // and then closed.
   preferences_->EnsureInitialized(
-      base::Bind(&MediaGalleriesDialogController::OnPreferencesInitialized,
+      base::Bind(&MediaGalleriesPermissionController::OnPreferencesInitialized,
                  base::Unretained(this)));
 
   // Unretained is safe because |this| owns |context_menu_|.
   context_menu_.reset(
       new MediaGalleryContextMenu(
-          base::Bind(&MediaGalleriesDialogController::DidForgetGallery,
+          base::Bind(&MediaGalleriesPermissionController::DidForgetEntry,
                      base::Unretained(this))));
 }
 
-void MediaGalleriesDialogController::OnPreferencesInitialized() {
+void MediaGalleriesPermissionController::OnPreferencesInitialized() {
   if (StorageMonitor::GetInstance())
     StorageMonitor::GetInstance()->AddObserver(this);
 
   // |preferences_| may be NULL in tests.
   if (preferences_) {
     preferences_->AddGalleryChangeObserver(this);
     InitializePermissions();
   }
 
   dialog_.reset(create_dialog_callback_.Run(this));
 }
 
-MediaGalleriesDialogController::MediaGalleriesDialogController(
+MediaGalleriesPermissionController::MediaGalleriesPermissionController(
     const extensions::Extension& extension,
     MediaGalleriesPreferences* preferences,
     const CreateDialogCallback& create_dialog_callback,
     const base::Closure& on_finish)
     : web_contents_(NULL),
       extension_(&extension),
       on_finish_(on_finish),
       preferences_(preferences),
       create_dialog_callback_(create_dialog_callback) {
   OnPreferencesInitialized();
 }
 
-MediaGalleriesDialogController::~MediaGalleriesDialogController() {
+MediaGalleriesPermissionController::~MediaGalleriesPermissionController() {
   if (StorageMonitor::GetInstance())
     StorageMonitor::GetInstance()->RemoveObserver(this);
 
   // |preferences_| may be NULL in tests.
   if (preferences_)
     preferences_->RemoveGalleryChangeObserver(this);
 
   if (select_folder_dialog_.get())
     select_folder_dialog_->ListenerDestroyed();
 }
 
-base::string16 MediaGalleriesDialogController::GetHeader() const {
+base::string16 MediaGalleriesPermissionController::GetHeader() const {
   return l10n_util::GetStringFUTF16(IDS_MEDIA_GALLERIES_DIALOG_HEADER,
                                     base::UTF8ToUTF16(extension_->name()));
 }
 
-base::string16 MediaGalleriesDialogController::GetSubtext() const {
+base::string16 MediaGalleriesPermissionController::GetSubtext() const {
   extensions::MediaGalleriesPermission::CheckParam copy_to_param(
       extensions::MediaGalleriesPermission::kCopyToPermission);
   extensions::MediaGalleriesPermission::CheckParam delete_param(
       extensions::MediaGalleriesPermission::kDeletePermission);
-  const extensions::PermissionsData* permissions_data =
+  const extensions::PermissionsData* permission_data =
       extension_->permissions_data();
-  bool has_copy_to_permission = permissions_data->CheckAPIPermissionWithParam(
+  bool has_copy_to_permission = permission_data->CheckAPIPermissionWithParam(
       APIPermission::kMediaGalleries, &copy_to_param);
-  bool has_delete_permission = permissions_data->CheckAPIPermissionWithParam(
+  bool has_delete_permission = permission_data->CheckAPIPermissionWithParam(
       APIPermission::kMediaGalleries, &delete_param);
 
   int id;
   if (has_copy_to_permission)
     id = IDS_MEDIA_GALLERIES_DIALOG_SUBTEXT_READ_WRITE;
   else if (has_delete_permission)
     id = IDS_MEDIA_GALLERIES_DIALOG_SUBTEXT_READ_DELETE;
   else
     id = IDS_MEDIA_GALLERIES_DIALOG_SUBTEXT_READ_ONLY;
 
   return l10n_util::GetStringFUTF16(id, base::UTF8ToUTF16(extension_->name()));
 }
 
-base::string16 MediaGalleriesDialogController::GetUnattachedLocationsHeader()
-    const {
-  return l10n_util::GetStringUTF16(IDS_MEDIA_GALLERIES_UNATTACHED_LOCATIONS);
-}
-
-bool MediaGalleriesDialogController::IsAcceptAllowed() const {
+bool MediaGalleriesPermissionController::IsAcceptAllowed() const {
   if (!toggled_galleries_.empty() || !forgotten_galleries_.empty())
     return true;
 
   for (GalleryPermissionsMap::const_iterator iter = new_galleries_.begin();
        iter != new_galleries_.end();
        ++iter) {
-    if (iter->second.allowed)
+    if (iter->second.selected)
       return true;
   }
 
   return false;
 }
 
+bool MediaGalleriesPermissionController::ShouldShowFolderViewer(
+    const Entry& entry) const {
+  return false;
+}
+
+std::vector<base::string16>
+MediaGalleriesPermissionController::GetSectionHeaders() const {
+  std::vector<base::string16> result;
+  result.push_back(base::string16());  // First section has no header.
+  result.push_back(
+      l10n_util::GetStringUTF16(IDS_MEDIA_GALLERIES_UNATTACHED_LOCATIONS));
+  return result;
+}
+
 // Note: sorts by display criterion: GalleriesVectorComparator.
-MediaGalleriesDialogController::GalleryPermissionsVector
-MediaGalleriesDialogController::FillPermissions(bool attached) const {
-  GalleryPermissionsVector result;
+MediaGalleriesDialogController::Entries
+MediaGalleriesPermissionController::GetSectionEntries(size_t index) const {
+  DCHECK_GT(2U, index);  // This dialog only has two sections.
+
+  // TODO(vandebo): Change this to be permitted/non-permitted instead of
+  // attached/non-attached.
+  bool attached = !index;
+  MediaGalleriesDialogController::Entries result;
   for (GalleryPermissionsMap::const_iterator iter = known_galleries_.begin();
        iter != known_galleries_.end(); ++iter) {
     if (!ContainsKey(forgotten_galleries_, iter->first) &&
         attached == iter->second.pref_info.IsGalleryAvailable()) {
       result.push_back(iter->second);
     }
   }
   for (GalleryPermissionsMap::const_iterator iter = new_galleries_.begin();
        iter != new_galleries_.end(); ++iter) {
     if (attached == iter->second.pref_info.IsGalleryAvailable()) {
       result.push_back(iter->second);
     }
   }
 
   std::sort(result.begin(), result.end(), GalleriesVectorComparator);
   return result;
 }
 
-MediaGalleriesDialogController::GalleryPermissionsVector
-MediaGalleriesDialogController::AttachedPermissions() const {
-  return FillPermissions(true);
+base::string16
+MediaGalleriesPermissionController::GetAuxiliaryButtonText() const {
+  return l10n_util::GetStringUTF16(IDS_MEDIA_GALLERIES_DIALOG_ADD_GALLERY);
 }
 
-MediaGalleriesDialogController::GalleryPermissionsVector
-MediaGalleriesDialogController::UnattachedPermissions() const {
-  return FillPermissions(false);
-}
-
-void MediaGalleriesDialogController::OnAddFolderClicked() {
+// This is the 'Add Folder' button.
+void MediaGalleriesPermissionController::DidClickAuxiliaryButton() {
   base::FilePath default_path =
       extensions::file_system_api::GetLastChooseEntryDirectory(
           extensions::ExtensionPrefs::Get(GetProfile()), extension_->id());
   if (default_path.empty())
     PathService::Get(base::DIR_USER_DESKTOP, &default_path);
   select_folder_dialog_ =
       ui::SelectFileDialog::Create(this, new ChromeSelectFilePolicy(NULL));
   select_folder_dialog_->SelectFile(
       ui::SelectFileDialog::SELECT_FOLDER,
       l10n_util::GetStringUTF16(IDS_MEDIA_GALLERIES_DIALOG_ADD_GALLERY_TITLE),
       default_path,
       NULL,
       0,
       base::FilePath::StringType(),
       web_contents_->GetTopLevelNativeWindow(),
       NULL);
 }
 
-void MediaGalleriesDialogController::DidToggleGallery(
-    GalleryDialogId gallery_id, bool enabled) {
+void MediaGalleriesPermissionController::DidToggleEntry(
+    GalleryDialogId gallery_id, bool selected) {
   // Check known galleries.
   GalleryPermissionsMap::iterator iter = known_galleries_.find(gallery_id);
   if (iter != known_galleries_.end()) {
-    if (iter->second.allowed == enabled)
+    if (iter->second.selected == selected)
       return;
 
-    iter->second.allowed = enabled;
+    iter->second.selected = selected;
     if (ContainsKey(toggled_galleries_, gallery_id))
       toggled_galleries_.erase(gallery_id);
     else
       toggled_galleries_.insert(gallery_id);
     return;
   }
 
   iter = new_galleries_.find(gallery_id);
   if (iter != new_galleries_.end())
-    iter->second.allowed = enabled;
+    iter->second.selected = selected;
 
   // Don't sort -- the dialog is open, and we don't want to adjust any
   // positions for future updates to the dialog contents until they are
   // redrawn.
 }
 
-void MediaGalleriesDialogController::DidForgetGallery(
+void MediaGalleriesPermissionController::DidClickOpenFolderViewer(
+    GalleryDialogId gallery_id) {
+  NOTREACHED();
+}
+
+void MediaGalleriesPermissionController::DidForgetEntry(
     GalleryDialogId gallery_id) {
   media_galleries::UsageCount(media_galleries::DIALOG_FORGET_GALLERY);
   if (!new_galleries_.erase(gallery_id)) {
     DCHECK(ContainsKey(known_galleries_, gallery_id));
     forgotten_galleries_.insert(gallery_id);
   }
   dialog_->UpdateGalleries();
 }
 
-void MediaGalleriesDialogController::DialogFinished(bool accepted) {
+base::string16 MediaGalleriesPermissionController::GetAcceptButtonText() const {
+  return l10n_util::GetStringUTF16(IDS_MEDIA_GALLERIES_DIALOG_CONFIRM);
+}
+
+void MediaGalleriesPermissionController::DialogFinished(bool accepted) {
   // The dialog has finished, so there is no need to watch for more updates
   // from |preferences_|.
   // |preferences_| may be NULL in tests.
   if (preferences_)
     preferences_->RemoveGalleryChangeObserver(this);
 
   if (accepted)
     SavePermissions();
 
   on_finish_.Run();
 
   delete this;
 }
 
-content::WebContents* MediaGalleriesDialogController::web_contents() {
+content::WebContents* MediaGalleriesPermissionController::WebContents() {
   return web_contents_;
 }
 
-void MediaGalleriesDialogController::FileSelected(const base::FilePath& path,
-                                                  int /*index*/,
-                                                  void* /*params*/) {
+void MediaGalleriesPermissionController::FileSelected(
+    const base::FilePath& path,
+    int /*index*/,
+    void* /*params*/) {
   extensions::file_system_api::SetLastChooseEntryDirectory(
       extensions::ExtensionPrefs::Get(GetProfile()),
       extension_->id(),
       path);
 
   // Try to find it in the prefs.
   MediaGalleryPrefInfo gallery;
   DCHECK(preferences_);
   bool gallery_exists = preferences_->LookUpGalleryByPath(path, &gallery);
   if (gallery_exists && !gallery.IsBlackListedType()) {
     // The prefs are in sync with |known_galleries_|, so it should exist in
     // |known_galleries_| as well. User selecting a known gallery effectively
     // just sets the gallery to permitted.
     GalleryDialogId gallery_id = GetDialogId(gallery.pref_id);
     GalleryPermissionsMap::iterator iter = known_galleries_.find(gallery_id);
     DCHECK(iter != known_galleries_.end());
-    iter->second.allowed = true;
+    iter->second.selected = true;
     forgotten_galleries_.erase(gallery_id);
     dialog_->UpdateGalleries();
     return;
   }
 
   // Try to find it in |new_galleries_| (user added same folder twice).
   for (GalleryPermissionsMap::iterator iter = new_galleries_.begin();
        iter != new_galleries_.end(); ++iter) {
     if (iter->second.pref_info.path == gallery.path &&
         iter->second.pref_info.device_id == gallery.device_id) {
-      iter->second.allowed = true;
+      iter->second.selected = true;
       dialog_->UpdateGalleries();
       return;
     }
   }
 
   // Lastly, if not found, add a new gallery to |new_galleries_|.
-  // Note that it will have prefId = kInvalidMediaGalleryPrefId.
-  GalleryDialogId gallery_id = GetDialogId(gallery.pref_id);
-  new_galleries_[gallery_id] = GalleryPermission(gallery_id, gallery, true);
+  DCHECK_EQ(kInvalidMediaGalleryPrefId, gallery.pref_id);
+  gallery.pref_id = GetDialogId(kInvalidMediaGalleryPrefId);
+  new_galleries_[gallery.pref_id] = Entry(gallery, true);
   dialog_->UpdateGalleries();
 }
 
-void MediaGalleriesDialogController::OnRemovableStorageAttached(
+void MediaGalleriesPermissionController::OnRemovableStorageAttached(
     const StorageInfo& info) {
   UpdateGalleriesOnDeviceEvent(info.device_id());
 }
 
-void MediaGalleriesDialogController::OnRemovableStorageDetached(
+void MediaGalleriesPermissionController::OnRemovableStorageDetached(
     const StorageInfo& info) {
   UpdateGalleriesOnDeviceEvent(info.device_id());
 }
 
-void MediaGalleriesDialogController::OnPermissionAdded(
+void MediaGalleriesPermissionController::OnPermissionAdded(
     MediaGalleriesPreferences* /* prefs */,
     const std::string& extension_id,
     MediaGalleryPrefId /* pref_id */) {
   if (extension_id != extension_->id())
     return;
   UpdateGalleriesOnPreferencesEvent();
 }
 
-void MediaGalleriesDialogController::OnPermissionRemoved(
+void MediaGalleriesPermissionController::OnPermissionRemoved(
     MediaGalleriesPreferences* /* prefs */,
     const std::string& extension_id,
     MediaGalleryPrefId /* pref_id */) {
   if (extension_id != extension_->id())
     return;
   UpdateGalleriesOnPreferencesEvent();
 }
 
-void MediaGalleriesDialogController::OnGalleryAdded(
+void MediaGalleriesPermissionController::OnGalleryAdded(
     MediaGalleriesPreferences* /* prefs */,
     MediaGalleryPrefId /* pref_id */) {
   UpdateGalleriesOnPreferencesEvent();
 }
 
-void MediaGalleriesDialogController::OnGalleryRemoved(
+void MediaGalleriesPermissionController::OnGalleryRemoved(
     MediaGalleriesPreferences* /* prefs */,
     MediaGalleryPrefId /* pref_id */) {
   UpdateGalleriesOnPreferencesEvent();
 }
 
-void MediaGalleriesDialogController::OnGalleryInfoUpdated(
+void MediaGalleriesPermissionController::OnGalleryInfoUpdated(
     MediaGalleriesPreferences* prefs,
     MediaGalleryPrefId pref_id) {
   DCHECK(preferences_);
   const MediaGalleriesPrefInfoMap& pref_galleries =
       preferences_->known_galleries();
   MediaGalleriesPrefInfoMap::const_iterator pref_it =
       pref_galleries.find(pref_id);
   if (pref_it == pref_galleries.end())
     return;
   const MediaGalleryPrefInfo& gallery_info = pref_it->second;
   UpdateGalleriesOnDeviceEvent(gallery_info.device_id);
 }
 
-void MediaGalleriesDialogController::InitializePermissions() {
+void MediaGalleriesPermissionController::InitializePermissions() {
   known_galleries_.clear();
   DCHECK(preferences_);
   const MediaGalleriesPrefInfoMap& galleries = preferences_->known_galleries();
   for (MediaGalleriesPrefInfoMap::const_iterator iter = galleries.begin();
        iter != galleries.end();
        ++iter) {
     const MediaGalleryPrefInfo& gallery = iter->second;
     if (gallery.IsBlackListedType())
       continue;
 
     GalleryDialogId gallery_id = GetDialogId(gallery.pref_id);
-    known_galleries_[gallery_id] =
-        GalleryPermission(gallery_id, gallery, false);
+    known_galleries_[gallery_id] = Entry(gallery, false);
+    known_galleries_[gallery_id].pref_info.pref_id = gallery_id;
   }
 
   MediaGalleryPrefIdSet permitted =
       preferences_->GalleriesForExtension(*extension_);
 
   for (MediaGalleryPrefIdSet::iterator iter = permitted.begin();
        iter != permitted.end(); ++iter) {
     GalleryDialogId gallery_id = GetDialogId(*iter);
     if (ContainsKey(toggled_galleries_, gallery_id))
       continue;
     DCHECK(ContainsKey(known_galleries_, gallery_id));
-    known_galleries_[gallery_id].allowed = true;
+    known_galleries_[gallery_id].selected = true;
   }
 }
 
-void MediaGalleriesDialogController::SavePermissions() {
+void MediaGalleriesPermissionController::SavePermissions() {
   DCHECK(preferences_);
   media_galleries::UsageCount(media_galleries::SAVE_DIALOG);
   for (GalleryPermissionsMap::const_iterator iter = known_galleries_.begin();
        iter != known_galleries_.end(); ++iter) {
-    MediaGalleryPrefId pref_id = iter->second.pref_info.pref_id;
+    MediaGalleryPrefId pref_id = GetPrefId(iter->first);
     if (ContainsKey(forgotten_galleries_, iter->first)) {
       preferences_->ForgetGalleryById(pref_id);
     } else {
       bool changed = preferences_->SetGalleryPermissionForExtension(
-          *extension_, pref_id, iter->second.allowed);
+          *extension_, pref_id, iter->second.selected);
       if (changed) {
-        if (iter->second.allowed) {
+        if (iter->second.selected) {
           media_galleries::UsageCount(
               media_galleries::DIALOG_PERMISSION_ADDED);
         } else {
           media_galleries::UsageCount(
               media_galleries::DIALOG_PERMISSION_REMOVED);
         }
       }
     }
   }
 
   for (GalleryPermissionsMap::const_iterator iter = new_galleries_.begin();
        iter != new_galleries_.end(); ++iter) {
     media_galleries::UsageCount(media_galleries::DIALOG_GALLERY_ADDED);
     // If the user added a gallery then unchecked it, forget about it.
-    if (!iter->second.allowed)
+    if (!iter->second.selected)
       continue;
 
     const MediaGalleryPrefInfo& gallery = iter->second.pref_info;
     MediaGalleryPrefId id = preferences_->AddGallery(
         gallery.device_id, gallery.path, MediaGalleryPrefInfo::kUserAdded,
         gallery.volume_label, gallery.vendor_name, gallery.model_name,
         gallery.total_size_in_bytes, gallery.last_attach_time, 0, 0, 0);
     preferences_->SetGalleryPermissionForExtension(*extension_, id, true);
   }
 }
 
-void MediaGalleriesDialogController::UpdateGalleriesOnPreferencesEvent() {
+void MediaGalleriesPermissionController::UpdateGalleriesOnPreferencesEvent() {
   // Merge in the permissions from |preferences_|. Afterwards,
   // |known_galleries_| may contain galleries that no longer belong there,
   // but the code below will put |known_galleries_| back in a consistent state.
   InitializePermissions();
 
   std::set<GalleryDialogId> new_galleries_to_remove;
   // Look for duplicate entries in |new_galleries_| in case one was added
   // in another dialog.
   for (GalleryPermissionsMap::iterator it = known_galleries_.begin();
        it != known_galleries_.end();
        ++it) {
-    GalleryPermission& gallery = it->second;
+    Entry& gallery = it->second;
     for (GalleryPermissionsMap::iterator new_it = new_galleries_.begin();
          new_it != new_galleries_.end();
          ++new_it) {
       if (new_it->second.pref_info.path == gallery.pref_info.path &&
           new_it->second.pref_info.device_id == gallery.pref_info.device_id) {
         // Found duplicate entry. Get the existing permission from it and then
         // remove it.
-        gallery.allowed = new_it->second.allowed;
+        gallery.selected = new_it->second.selected;
         new_galleries_to_remove.insert(new_it->first);
         break;
       }
     }
   }
   for (std::set<GalleryDialogId>::const_iterator it =
            new_galleries_to_remove.begin();
        it != new_galleries_to_remove.end();
        ++it) {
     new_galleries_.erase(*it);
   }
 
   dialog_->UpdateGalleries();
 }
 
-void MediaGalleriesDialogController::UpdateGalleriesOnDeviceEvent(
+void MediaGalleriesPermissionController::UpdateGalleriesOnDeviceEvent(
     const std::string& device_id) {
   dialog_->UpdateGalleries();
 }
 
-ui::MenuModel* MediaGalleriesDialogController::GetContextMenu(
+ui::MenuModel* MediaGalleriesPermissionController::GetContextMenu(
     GalleryDialogId gallery_id) {
   context_menu_->set_pref_id(gallery_id);
   return context_menu_.get();
 }
 
-GalleryDialogId MediaGalleriesDialogController::GetDialogId(
+GalleryDialogId MediaGalleriesPermissionController::GetDialogId(
     MediaGalleryPrefId pref_id) {
   return id_map_.GetDialogId(pref_id);
 }
 
-Profile* MediaGalleriesDialogController::GetProfile() {
+MediaGalleryPrefId MediaGalleriesPermissionController::GetPrefId(
+    GalleryDialogId id) {
+  return id_map_.GetPrefId(id);
+}
+
+Profile* MediaGalleriesPermissionController::GetProfile() {
   return Profile::FromBrowserContext(web_contents_->GetBrowserContext());
 }
 
-MediaGalleriesDialogController::DialogIdMap::DialogIdMap()
+MediaGalleriesPermissionController::DialogIdMap::DialogIdMap()
     : next_dialog_id_(1) {
+  // Dialog id of 0 is invalid, so fill the slot.
+  forward_mapping_.push_back(kInvalidMediaGalleryPrefId);
 }
 
-MediaGalleriesDialogController::DialogIdMap::~DialogIdMap() {
+MediaGalleriesPermissionController::DialogIdMap::~DialogIdMap() {
 }
 
 GalleryDialogId
-MediaGalleriesDialogController::DialogIdMap::GetDialogId(
+MediaGalleriesPermissionController::DialogIdMap::GetDialogId(
     MediaGalleryPrefId pref_id) {
   std::map<GalleryDialogId, MediaGalleryPrefId>::const_iterator it =
-      mapping_.find(pref_id);
-  if (it != mapping_.end())
+      back_map_.find(pref_id);
+  if (it != back_map_.end())
     return it->second;
 
   GalleryDialogId result = next_dialog_id_++;
+  DCHECK_EQ(result, forward_mapping_.size());
+  forward_mapping_.push_back(pref_id);
   if (pref_id != kInvalidMediaGalleryPrefId)
-    mapping_[pref_id] = result;
+    back_map_[pref_id] = result;
   return result;
 }
 
+MediaGalleryPrefId
+MediaGalleriesPermissionController::DialogIdMap::GetPrefId(
+    GalleryDialogId id) {
+  DCHECK_LT(id, next_dialog_id_);
+  return forward_mapping_[id];
+}
+
 // MediaGalleries dialog -------------------------------------------------------
 
 MediaGalleriesDialog::~MediaGalleriesDialog() {}