[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/media_galleries_preferences.h"
 #include "chrome/browser/media_galleries/mtp_device_delegate_impl.h"
 #include "chrome/browser/storage_monitor/removable_storage_observer.h"
 
 class Profile;
 
 namespace content {
 class RenderViewHost;
 }
@@ skipping 29 matching lines @@
   std::string fsid;
   MediaGalleryPrefId pref_id;
   std::string transient_device_id;
   bool removable;
   bool media_device;
 };
 
 typedef base::Callback<void(const std::vector<MediaFileSystemInfo>&)>
     MediaFileSystemsCallback;
 
-class MediaFileSystemRegistry : public RemovableStorageObserver {
+class MediaFileSystemRegistry : public RemovableStorageObserver,
+                                public MediaGalleriesPreferences::Vendor {
  public:
   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,
+      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 vendor.
+  // 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(
+      base::Callback<void(MediaGalleriesPreferences::Vendor*)> callback);
 
   // RemovableStorageObserver implementation.
   virtual void OnRemovableStorageDetached(const StorageInfo& info) OVERRIDE;
 
   size_t GetExtensionGalleriesHostCountForTests() const;
 
   // See TransientDeviceIds::GetTransientIdForDeviceId().
   uint64 GetTransientIdForDeviceId(const std::string& device_id);
 
+  // MediaGalleriesPreferences::Vendor
+  virtual MediaGalleriesPreferences* GetPreferences(Profile* profile) OVERRIDE;
+
  private:
   friend class TestMediaFileSystemContext;
   class MediaFileSystemContextImpl;
 
+  // Bottom half of |GetMediaFileSystemsForExtensions|, called after the
+  // StorageMonitor is initialized.
+  void GetMediaFileSystemsWithPreferences(
+      const content::RenderViewHost* rvh,
+      const extensions::Extension* extension,
+      const MediaFileSystemsCallback& callback,
+      MediaGalleriesPreferences::Vendor* vendor);
+
+  // Notify the registry when the storage monitor has been initialized.
+  void OnStorageMonitorInitialized(
+      base::Callback<void(MediaGalleriesPreferences::Vendor*)> 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;
 
   // Map a MTP or PTP device location to the raw pointer of
   // ScopedMTPDeviceMapEntry. It is safe to store a raw pointer in this
@@ skipping 19 matching lines @@
   // ExtensionGalleriesHost objects created.
   ExtensionGalleriesHostMap extension_hosts_map_;
 
   PrefChangeRegistrarMap pref_change_registrar_map_;
 
   // Only accessed on the UI thread.
   MTPDeviceDelegateMap mtp_device_delegate_map_;
 
   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_