Remount all removable storage devices upon policy update

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 facd03ca5e2cfc2ce790ac612eede5fbd8cea9e8..4464bb60c0cb9c27c5c8e5bd8ed3986cf3e1eee1 100644
--- a/chrome/browser/chromeos/file_manager/volume_manager.cc
+++ b/chrome/browser/chromeos/file_manager/volume_manager.cc
@@ -371,6 +371,10 @@ void VolumeManager::Initialize() {
       prefs::kExternalStorageDisabled,
       base::Bind(&VolumeManager::OnExternalStorageDisabledChanged,
                  weak_ptr_factory_.GetWeakPtr()));
+  pref_change_registrar_.Add(
+      prefs::kExternalStorageReadOnly,
+      base::Bind(&VolumeManager::OnExternalStorageReadOnlyChanged,
+                 weak_ptr_factory_.GetWeakPtr()));
 
   // Subscribe to storage monitor for MTP notifications.
   if (storage_monitor::StorageMonitor::GetInstance()) {
@@ -718,6 +722,11 @@ void VolumeManager::OnExternalStorageDisabledChanged() {
   }
 }
 
+void VolumeManager::OnExternalStorageReadOnlyChanged() {
+  disk_mount_manager_->RemountAllRemovableDrives(
+      GetExternalStorageAccessMode(profile_));
+}
+
 void VolumeManager::OnRemovableStorageAttached(
     const storage_monitor::StorageInfo& info) {
   if (!storage_monitor::StorageInfo::IsMTPDevice(info.device_id()))