[Media Galleries] Lazily initialize the storage monitor.

chrome/browser/extensions/api/media_galleries_private/gallery_watch_state_tracker.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.
 
 // GalleryWatchStateTracker implementation.
 
 #include "chrome/browser/extensions/api/media_galleries_private/gallery_watch_state_tracker.h"
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
@@ skipping 54 matching lines @@
 
 // Looks up an extension by ID. Does not include disabled extensions.
 const Extension* GetExtensionById(Profile* profile,
                                   const std::string& extension_id) {
   ExtensionService* service = profile->GetExtensionService();
   if (!service)
     return NULL;
   return service->GetExtensionById(extension_id, false);
 }
 
-// Returns the initialized media galleries preferences for the specified
-// |profile|.
-chrome::MediaGalleriesPreferences* GetMediaGalleryPreferences(
-    Profile* profile) {
-  return g_browser_process->media_file_system_registry()->GetPreferences(
-      profile);
-}
-
 }  // namespace
 
 GalleryWatchStateTracker::GalleryWatchStateTracker(Profile* profile)
-    : profile_(profile) {
+    : profile_(profile),
+      preferences_(NULL) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   DCHECK(profile_);
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_LOADED,
                  content::Source<Profile>(profile_));
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_UNLOADED,
                  content::Source<Profile>(profile_));
 }
 
 GalleryWatchStateTracker::~GalleryWatchStateTracker() {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
@@ skipping 56 matching lines @@
   if (extension_id_iter == watched_extensions_map_.end())
     return;
   const WatchedGalleriesMap& galleries = extension_id_iter->second;
   for (WatchedGalleriesMap::const_iterator gallery_id_iter = galleries.begin();
        gallery_id_iter != galleries.end(); ++gallery_id_iter)
     RemoveGalleryWatch(extension_id, gallery_id_iter->second);
   watched_extensions_map_.erase(extension_id_iter);
   WriteToStorage(extension_id);
 }
 
+void GalleryWatchStateTracker::SetPreferences(
+    chrome::MediaGalleriesPreferences* preferences) {
+  preferences_ = preferences;
+}
+
 void GalleryWatchStateTracker::OnGalleryWatchAdded(
     const std::string& extension_id,
     chrome::MediaGalleryPrefId gallery_id) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   bool update_storage =
       AddWatchedGalleryIdInfoForExtension(extension_id, gallery_id);
   if (update_storage)
     WriteToStorage(extension_id);
 }
 
@@ skipping 66 matching lines @@
       WatchedGalleryIdsToValue(gallery_ids).PassAs<base::Value>());
 }
 
 void GalleryWatchStateTracker::ReadFromStorage(const std::string& extension_id,
                                                scoped_ptr<base::Value> value) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   base::ListValue* list = NULL;
   if (!value.get() || !value->GetAsList(&list))
     return;
   chrome::MediaGalleryPrefIdSet gallery_ids = WatchedGalleryIdsFromValue(list);
+  if (gallery_ids.size() > 0) {
+    g_browser_process->media_file_system_registry()->GetPreferencesAsync(
+        profile_,
+        base::Bind(&GalleryWatchStateTracker::ReadFromStorageWithPreferences,
+                   AsWeakPtr(), extension_id, gallery_ids));
+  }
+}
+
+void GalleryWatchStateTracker::ReadFromStorageWithPreferences(
+    const std::string& extension_id,
+    chrome::MediaGalleryPrefIdSet gallery_ids,
+    chrome::MediaGalleriesPreferences* preferences) {
+  SetPreferences(preferences);

[Lei Zhang, 2013/05/14 04:12:23]

Do we need both this and the SetPreferences() call from
media_galleries_private_api.cc?

[Greg Billock, 2013/05/14 21:27:13]

I think they get touched in different paths. So there's redundancy, but I think
we need it.

+
   for (chrome::MediaGalleryPrefIdSet::const_iterator id_iter =
            gallery_ids.begin();
        id_iter != gallery_ids.end(); ++id_iter) {
     watched_extensions_map_[extension_id][*id_iter] = false;
     SetupGalleryWatch(extension_id, *id_iter);
   }
 }
 
 void GalleryWatchStateTracker::SetupGalleryWatch(
     const std::string& extension_id,
     chrome::MediaGalleryPrefId gallery_id) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   const Extension* extension = GetExtensionById(profile_, extension_id);
   DCHECK(extension);
-  base::FilePath gallery_file_path(
-      GetMediaGalleryPreferences(profile_)->LookUpGalleryPathForExtension(
-          gallery_id, extension, false));
+  DCHECK(preferences_);
+  base::FilePath gallery_file_path(preferences_->LookUpGalleryPathForExtension(
+      gallery_id, extension, false));
   if (gallery_file_path.empty())
     return;
   MediaGalleriesPrivateEventRouter* router =
       MediaGalleriesPrivateAPI::Get(profile_)->GetEventRouter();
   DCHECK(router);
   content::BrowserThread::PostTaskAndReplyWithResult(
       content::BrowserThread::FILE,
       FROM_HERE,
       base::Bind(&GalleryWatchManager::SetupGalleryWatch,
                  profile_,
                  gallery_id,
                  gallery_file_path,
                  extension_id,
                  router->AsWeakPtr()),
       base::Bind(&GalleryWatchStateTracker::HandleSetupGalleryWatchResponse,
                  AsWeakPtr(),
                  extension_id,
                  gallery_id));
 }
 
 void GalleryWatchStateTracker::RemoveGalleryWatch(
     const std::string& extension_id,
     chrome::MediaGalleryPrefId gallery_id) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   const Extension* extension = GetExtensionById(profile_, extension_id);
   DCHECK(extension);
-  base::FilePath gallery_file_path(
-      GetMediaGalleryPreferences(profile_)->LookUpGalleryPathForExtension(
-          gallery_id, extension, true));
+  DCHECK(preferences_);
+  base::FilePath gallery_file_path(preferences_->LookUpGalleryPathForExtension(
+      gallery_id, extension, true));
   if (gallery_file_path.empty())
     return;
   content::BrowserThread::PostTask(
       content::BrowserThread::FILE, FROM_HERE,
       base::Bind(&GalleryWatchManager::RemoveGalleryWatch,
                  profile_,
                  gallery_file_path,
                  extension_id));
   watched_extensions_map_[extension_id][gallery_id] = false;
 }
@@ skipping 23 matching lines @@
     const std::string& extension_id,
     chrome::MediaGalleryPrefId gallery_id) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   if (HasGalleryWatchInfo(extension_id, gallery_id, true))
     return false;
   watched_extensions_map_[extension_id][gallery_id] = true;
   return true;
 }
 
 }  // namespace extensions