Redesigned and refactored ScopedMTPDeviceMapEntry, MTPDeviceMapService & MTPDeviceDelegate classes.

chrome/browser/media_gallery/media_file_system_registry.h

Index: chrome/browser/media_gallery/media_file_system_registry.h
diff --git a/chrome/browser/media_gallery/media_file_system_registry.h b/chrome/browser/media_gallery/media_file_system_registry.h
index 1fc2ac1c5b285ec1aa3dbfb2bb19411bf4809836..ee8056c654f0a5f6ab0b5868e03b808e3b6c7b2e 100644
--- a/chrome/browser/media_gallery/media_file_system_registry.h
+++ b/chrome/browser/media_gallery/media_file_system_registry.h
@@ -9,6 +9,7 @@
 #define CHROME_BROWSER_MEDIA_GALLERY_MEDIA_FILE_SYSTEM_REGISTRY_H_
 
 #include <map>
+#include <set>
 #include <string>
 #include <utility>
 #include <vector>
@@ -17,7 +18,6 @@
 #include "base/lazy_instance.h"
 #include "base/file_path.h"
 #include "base/memory/ref_counted.h"
-#include "base/memory/weak_ptr.h"
 #include "base/prefs/public/pref_change_registrar.h"
 #include "base/prefs/public/pref_observer.h"
 #include "base/system_monitor/system_monitor.h"
@@ -64,12 +64,16 @@ class MediaFileSystemContext {
       const std::string& device_id, const FilePath& path) = 0;
 
 #if defined(SUPPORT_MTP_DEVICE_FILESYSTEM)
-  // Registers and returns the file system id for the MTP or PTP device
-  // specified by |device_id| and |path|. Updates |entry| with the corresponding
-  // ScopedMTPDeviceMapEntry object.
+  // For the given |galleries_host|, this function returns the file system id
+  // of the registered MTP or PTP device specified by |device_id| and |path|.
   virtual std::string RegisterFileSystemForMTPDevice(
       const std::string& device_id, const FilePath& path,
-      scoped_refptr<ScopedMTPDeviceMapEntry>* entry) = 0;
+      const ExtensionGalleriesHost* galleries_host) = 0;
+
+  // Removes the MTP or PTP device reference for the given |galleries_host|.
+  virtual void RemoveMTPDeviceReferenceForHost(
+      const FilePath::StringType& device_location,
+      const ExtensionGalleriesHost* galleries_host) = 0;
 #endif
 
   // Revoke the passed |fsid|.
@@ -120,11 +124,19 @@ class MediaFileSystemRegistry
   typedef std::map<Profile*, PrefChangeRegistrar*> PrefChangeRegistrarMap;
 
 #if defined(SUPPORT_MTP_DEVICE_FILESYSTEM)
-  // Map a MTP or PTP device location to the weak pointer of
-  // ScopedMTPDeviceMapEntry.
-  typedef std::map<const FilePath::StringType,
-                   base::WeakPtr<ScopedMTPDeviceMapEntry> >
+  // Map a MTP or PTP device location to the ScopedMTPDeviceMapEntry.
+  // This map owns ScopedMTPDeviceMapEntry.
+  typedef std::map<const FilePath::StringType, ScopedMTPDeviceMapEntry*>
       MTPDeviceDelegateMap;
+
+  // Set of extension galleries host.
+  typedef std::set<const ExtensionGalleriesHost*> ExtensionGalleriesHostSet;
+
+  // Map a device location to a set of extension galleries host.
+  // This map keeps track of extension galleries that currently registered
+  // the MTP device gallery as a file system.
+  typedef std::map<const FilePath::StringType, ExtensionGalleriesHostSet>
+      MTPDeviceReferencesMap;
 #endif
 
   // Obtain an instance of this class via GetInstance().
@@ -136,14 +148,17 @@ class MediaFileSystemRegistry
                                    const std::string& pref_name) OVERRIDE;
 
 #if defined(SUPPORT_MTP_DEVICE_FILESYSTEM)
-  // Returns ScopedMTPDeviceMapEntry object for the given |device_location|.
-  ScopedMTPDeviceMapEntry* GetOrCreateScopedMTPDeviceMapEntry(
-      const FilePath::StringType& device_location);
+  // Adds the |galleries_host| reference for the MTP device specified by the
+  // |device_location|.
+  void AddGalleriesHostReferenceForMTPDevice(
+      const FilePath::StringType& device_location,
+      const ExtensionGalleriesHost* galleries_host);
 
-  // Removes the ScopedMTPDeviceMapEntry associated with the given
+  // Removes the |galleries_host| reference for the MTP device specified by the
   // |device_location|.
-  void RemoveScopedMTPDeviceMapEntry(
-      const FilePath::StringType& device_location);
+  void RemoveGalleriesHostReferenceForMTPDevice(
+      const FilePath::StringType& device_location,
+      const ExtensionGalleriesHost* galleries_host);
 #endif
 
   void OnExtensionGalleriesHostEmpty(Profile* profile,
@@ -157,7 +172,8 @@ class MediaFileSystemRegistry
 
 #if defined(SUPPORT_MTP_DEVICE_FILESYSTEM)
   // Only accessed on the UI thread.
-  MTPDeviceDelegateMap mtp_delegate_map_;
+  MTPDeviceDelegateMap mtp_device_delegate_map_;
+  MTPDeviceReferencesMap mtp_device_references_map_;
 #endif
 
   scoped_ptr<MediaFileSystemContext> file_system_context_;