[Media Galleries] Lazily initialize the storage monitor.

chrome/browser/media_galleries/media_file_system_registry.h

 // 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.
 
 // MediaFileSystemRegistry registers pictures directories and media devices as
 // File API filesystems and keeps track of the path to filesystem ID mappings.
 
 #ifndef CHROME_BROWSER_MEDIA_GALLERIES_MEDIA_FILE_SYSTEM_REGISTRY_H_
 #define CHROME_BROWSER_MEDIA_GALLERIES_MEDIA_FILE_SYSTEM_REGISTRY_H_
 
 #include <map>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/files/file_path.h"
 #include "base/memory/ref_counted.h"
+#include "base/memory/weak_ptr.h"
 #include "base/prefs/pref_change_registrar.h"
 #include "chrome/browser/media_galleries/fileapi/mtp_device_file_system_config.h"
 #include "chrome/browser/media_galleries/media_galleries_preferences.h"
 #include "chrome/browser/storage_monitor/removable_storage_observer.h"
 
 #if defined(SUPPORT_MTP_DEVICE_FILESYSTEM)
 #include "chrome/browser/media_galleries/mtp_device_delegate_impl.h"
 #endif
 
 class Profile;
@@ skipping 45 matching lines @@
   MediaFileSystemRegistry();
   virtual ~MediaFileSystemRegistry();
 
   // Passes to |callback| the list of media filesystem IDs and paths for a
   // given RVH. Called on the UI thread.
   void GetMediaFileSystemsForExtension(
       const content::RenderViewHost* rvh,
       const extensions::Extension* extension,
       const MediaFileSystemsCallback& callback);
 
-  // Returns the initialized media galleries preferences for the specified
-  // |profile|. This method should be used instead of calling
+  // Call the given callback with preferences. This is asynchronous so that
+  // StorageMonitor may be initialized lazily in order to set up the returned
+  // preferences.
+  // This method should be used instead of calling
   // MediaGalleriesPreferences directly because this method also ensures that
   // currently attached removable devices are added to the preferences.
   // Called on the UI thread.
-  MediaGalleriesPreferences* GetPreferences(Profile* profile);
+  void GetPreferencesAsync(

[vandebo (ex-Chrome), 2013/05/17 22:19:58]

nit picky: maybe leave this name the same and rename the private one
GetPreferencesInternal?  Since it takes a callback it's kind of obvious that it
is async...

[Greg Billock, 2013/05/18 06:28:40]

Fiddled this with the new interface.

+      Profile* profile,
+      base::Callback<void(MediaGalleriesPreferences*)> callback);
 
   // RemovableStorageObserver implementation.
   virtual void OnRemovableStorageDetached(const StorageInfo& info) OVERRIDE;
 
   size_t GetExtensionGalleriesHostCountForTests() const;
 
   // See TransientDeviceIds::GetTransientIdForDeviceId().
   uint64 GetTransientIdForDeviceId(const std::string& device_id);
 
  private:
   friend class TestMediaFileSystemContext;
   class MediaFileSystemContextImpl;
 
+  MediaGalleriesPreferences* GetPreferences(Profile* profile);
+
+  // Bottom half of |GetMediaFileSystemsForExtensions|, called after the
+  // StorageMonitor is initialized.
+  void GetMediaFileSystemsPostStorageMonitorInit(

[vandebo (ex-Chrome), 2013/05/17 22:19:58]

GetMediaFileSystemsWithPreferences ?

[Greg Billock, 2013/05/18 06:28:40]

Done.

+      const content::RenderViewHost* rvh,
+      const extensions::Extension* extension,
+      const MediaFileSystemsCallback& callback,
+      MediaGalleriesPreferences* preferences);
+
+  // Notify the registry when the storage monitor has been initialized.
+  void OnStorageMonitorInitialized(
+      Profile* profile,
+      base::Callback<void(MediaGalleriesPreferences*)> callback);
+
   // Map an extension to the ExtensionGalleriesHost.
   typedef std::map<std::string /*extension_id*/,
                    scoped_refptr<ExtensionGalleriesHost> > ExtensionHostMap;
   // Map a profile and extension to the ExtensionGalleriesHost.
   typedef std::map<Profile*, ExtensionHostMap> ExtensionGalleriesHostMap;
   // Map a profile to a PrefChangeRegistrar.
   typedef std::map<Profile*, PrefChangeRegistrar*> PrefChangeRegistrarMap;
 
 #if defined(SUPPORT_MTP_DEVICE_FILESYSTEM)
   // Map a MTP or PTP device location to the raw pointer of
@@ skipping 25 matching lines @@
 
   PrefChangeRegistrarMap pref_change_registrar_map_;
 
 #if defined(SUPPORT_MTP_DEVICE_FILESYSTEM)
   // Only accessed on the UI thread.
   MTPDeviceDelegateMap mtp_device_delegate_map_;
 #endif
 
   scoped_ptr<MediaFileSystemContext> file_system_context_;
 
+  base::WeakPtrFactory<MediaFileSystemRegistry> weak_ptr_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(MediaFileSystemRegistry);
 };
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_MEDIA_GALLERIES_MEDIA_FILE_SYSTEM_REGISTRY_H_