IndexedDB: Remove WebData usage from frontend

Bug: 717812
Change-Id: I4d69b9b5093df319f7c47df3c93794108a0bb451
Reviewed-on: https://chromium-review.googlesource.com/c/1364301
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Chase Phillips <cmp@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615989}
16 files changed