this is the first part of https://codereview.chromium.org/1012633002.
mechanical change.

The motivation: the original patch needs to use List of List but list is not copiable.

BUG=chromium:452067
LOG=n

Review URL: https://codereview.chromium.org/1011733002

Cr-Commit-Position: refs/heads/master@{#27221}