Add history strings for accessibility label and entry deletion

Adds strings to history_strings for the accessibility label to describe
a history entry and accessibility action to delete a history entry.

BUG=590062

Review-Url: https://codereview.chromium.org/1960343002
Cr-Commit-Position: refs/heads/master@{#392644}
1 file changed