IndexedDB: Map mojom key to blink IDBKey

Bug: 717812
Change-Id: I59d74bd808e2a7e30264ec3a8dafd30964552f0a
Reviewed-on: https://chromium-review.googlesource.com/c/1354334
Commit-Queue: Chase Phillips <cmp@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#614438}
37 files changed