[Media Gallery] Added code to support mtp device media file system on Windows.

chrome/browser/media_gallery/media_file_system_registry.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.
 
 // MediaFileSystemRegistry implementation.
 
 #include "chrome/browser/media_gallery/media_file_system_registry.h"
 
 #include <set>
 #include <vector>
 
 #include "base/bind.h"
 #include "base/callback.h"
+#include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/json/json_writer.h"
 #include "base/path_service.h"
 #include "base/stl_util.h"
 #include "base/string_util.h"
 #include "base/system_monitor/system_monitor.h"
 #include "base/utf_string_conversions.h"
 #include "base/values.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/extension_system.h"
 #include "chrome/browser/media_gallery/media_file_system_context.h"
 #include "chrome/browser/media_gallery/media_galleries_preferences.h"
 #include "chrome/browser/media_gallery/media_galleries_preferences_factory.h"
 #include "chrome/browser/media_gallery/scoped_mtp_device_map_entry.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/system_monitor/media_storage_util.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/chrome_paths.h"
+#include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension_constants.h"
 #include "chrome/common/extensions/extension_set.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/notification_types.h"
@@ skipping 12 matching lines @@
 
 namespace chrome {
 
 namespace {
 
 struct InvalidatedGalleriesInfo {
   std::set<ExtensionGalleriesHost*> extension_hosts;
   std::set<MediaGalleryPrefId> pref_ids;
 };
 
+#if defined(SUPPORT_MTP_DEVICE_FILESYSTEM)
+// Returns true if the media transfer protocol (MTP) device operations are
+// allowed for this platform.
+// TODO(kmadhusu): Remove this function after fixing crbug.com/154835.
+bool IsMTPDeviceMediaOperationsEnabled() {
+#if defined(OS_WIN)
+  return CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kEnableMediaTransferProtocolDeviceOperations);
+#endif
+  return true;
+}
+#endif
+
 }  // namespace
 
 MediaFileSystemInfo::MediaFileSystemInfo(const std::string& fs_name,
                                          const FilePath& fs_path,
                                          const std::string& filesystem_id)
     : name(fs_name),
       path(fs_path),
       fsid(filesystem_id) {
 }
 
@@ skipping 60 matching lines @@
   // Revoke the file system for |id| if this extension has created one for |id|.
   void RevokeGalleryByPrefId(MediaGalleryPrefId id) {
     PrefIdFsInfoMap::iterator gallery = pref_id_map_.find(id);
     if (gallery == pref_id_map_.end())
       return;
 
     file_system_context_->RevokeFileSystem(gallery->second.fsid);
     pref_id_map_.erase(gallery);
 
 #if defined(SUPPORT_MTP_DEVICE_FILESYSTEM)
-    MediaDeviceEntryReferencesMap::iterator mtp_device_host =
-        media_device_map_references_.find(id);
-    if (mtp_device_host != media_device_map_references_.end())
-      media_device_map_references_.erase(mtp_device_host);
+    if (IsMTPDeviceMediaOperationsEnabled()) {
+      MediaDeviceEntryReferencesMap::iterator mtp_device_host =
+          media_device_map_references_.find(id);
+      if (mtp_device_host != media_device_map_references_.end())
+        media_device_map_references_.erase(mtp_device_host);
+    }
 #endif
 
     if (pref_id_map_.empty()) {
       rph_refs_.clear();
       CleanUp();
     }
   }
 
   // Indicate that the passed |rvh| will reference the file system ids created
   // by this class.  It is safe to call this multiple times with the same RVH.
@@ skipping 99 matching lines @@
       FilePath path = gallery_info.AbsolutePath();
       if (!MediaStorageUtil::CanCreateFileSystem(device_id, path))
         continue;
 
       std::string fsid;
       if (MediaStorageUtil::IsMassStorageDevice(device_id)) {
         fsid = file_system_context_->RegisterFileSystemForMassStorage(
             device_id, path);
       } else {
 #if defined(SUPPORT_MTP_DEVICE_FILESYSTEM)
+        if (!IsMTPDeviceMediaOperationsEnabled())
+          continue;
+
         scoped_refptr<ScopedMTPDeviceMapEntry> mtp_device_host;
         fsid = file_system_context_->RegisterFileSystemForMTPDevice(
             device_id, path, &mtp_device_host);
         DCHECK(mtp_device_host.get());
         media_device_map_references_[pref_id] = mtp_device_host;
 #else
         NOTIMPLEMENTED();
         continue;
 #endif
       }
@@ skipping 461 matching lines @@
 
     PrefChangeRegistrarMap::iterator pref_it =
         pref_change_registrar_map_.find(profile);
     DCHECK(pref_it != pref_change_registrar_map_.end());
     delete pref_it->second;
     pref_change_registrar_map_.erase(pref_it);
   }
 }
 
 }  // namespace chrome