Use .volume_label property for notifying MTP volume labels.

chrome/browser/chromeos/file_manager/volume_manager.cc

Index: chrome/browser/chromeos/file_manager/volume_manager.cc
diff --git a/chrome/browser/chromeos/file_manager/volume_manager.cc b/chrome/browser/chromeos/file_manager/volume_manager.cc
index 829e1972283e30bf8a884b25c07d34ddb24747c5..cb1f8ed789925eec8c6217517ac51ed8ebae6c66 100644
--- a/chrome/browser/chromeos/file_manager/volume_manager.cc
+++ b/chrome/browser/chromeos/file_manager/volume_manager.cc
@@ -729,9 +729,9 @@ void VolumeManager::OnRemovableStorageAttached(
   const std::string base_name = base::UTF16ToUTF8(info.model_name());
 
   // Assign a fresh volume ID based on the volume name.
-  std::string id = kMtpVolumeIdPrefix + base_name;
-  for (int i = 2; mounted_volumes_.count(id); ++i)
-    id = kMtpVolumeIdPrefix + base_name + base::StringPrintf(" (%d)", i);
+  std::string label = base_name;
+  for (int i = 2; mounted_volumes_.count(kMtpVolumeIdPrefix + label); ++i)
+    label = base_name + base::StringPrintf(" (%d)", i);
 
   bool result =
       fileapi::ExternalMountPoints::GetSystemInstance()->RegisterFileSystem(
@@ -750,7 +750,8 @@ void VolumeManager::OnRemovableStorageAttached(
   volume_info.mount_condition = chromeos::disks::MOUNT_CONDITION_NONE;
   volume_info.is_parent = true;
   volume_info.is_read_only = true;
-  volume_info.volume_id = id;
+  volume_info.volume_id = kMtpVolumeIdPrefix + label;
+  volume_info.volume_label = label;
   volume_info.source_path = path;
   volume_info.device_type = chromeos::DEVICE_TYPE_MOBILE;
   DoMountEvent(chromeos::MOUNT_ERROR_NONE, volume_info, false);