Change access mode of disk devices when mounting based on config.

chrome/browser/chromeos/extensions/file_manager/private_api_mount.cc

Index: chrome/browser/chromeos/extensions/file_manager/private_api_mount.cc
diff --git a/chrome/browser/chromeos/extensions/file_manager/private_api_mount.cc b/chrome/browser/chromeos/extensions/file_manager/private_api_mount.cc
index 2943bbff1f4aa3af1d072578fcf78287cdcfd73e..3da5dc94a809ca74969d0cd0b04749c1fb91f748 100644
--- a/chrome/browser/chromeos/extensions/file_manager/private_api_mount.cc
+++ b/chrome/browser/chromeos/extensions/file_manager/private_api_mount.cc
@@ -163,8 +163,8 @@ void FileManagerPrivateAddMountFunction::RunAfterMarkCacheFileAsMounted(
   disk_mount_manager->MountPath(
       file_path.AsUTF8Unsafe(),
       base::FilePath(display_name.Extension()).AsUTF8Unsafe(),
-      display_name.AsUTF8Unsafe(),
-      chromeos::MOUNT_TYPE_ARCHIVE);
+      display_name.AsUTF8Unsafe(), chromeos::MOUNT_TYPE_ARCHIVE,
+      chromeos::MOUNT_ACCESS_MODE_READ_WRITE);
 }
 
 bool FileManagerPrivateRemoveMountFunction::RunAsync() {