[TabSelectionEditor] Add strings

Change-Id: If3d333382233c155e4882e04fb3e9acbc14ea109
Bug: 970982
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1644525
Commit-Queue: Mei Liang <meiliang@chromium.org>
Reviewed-by: Wei-Yin Chen (陳威尹) <wychen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#666458}
6 files changed