GitLab

Use OnceCompletionCallback in AppCacheResponseReader (ReadInfo and
ReadData)

TBR=michaeln@chromium.org

Bug: 714018
Change-Id: Ide4ee3a281f4318c66014302c4bb596cff000d27
Reviewed-on: https://chromium-review.googlesource.com/675725Reviewed-by: Mark Pilgrim <pilgrim@chromium.org>
Commit-Queue: Mark Pilgrim <pilgrim@chromium.org>
Cr-Commit-Position: refs/heads/master@{#503430}