Pass through the response code and headers in Background Fetch

Pass through the response code and headers in Background Fetch

Following this CL, Background Fetch responses will include the response
code and headers as provided by the download manager.

We don't yet support the `backgroundfetchfail` event or handle CORS, but
those can now be implemented in follow-up CLs.

BUG=709489
Review-Url: https://codereview.chromium.org/2814683003
Cr-Commit-Position: refs/heads/master@{#464119}
Committed: https://chromium.googlesource.com/chromium/src/+/0b6bb8eb5aa2c306f7ad88a746bbec775c18b103

[Peter Beverloo, 2017-04-11 18:16:38]

peter@chromium.org changed reviewers:
+ harkness@chromium.org

[Peter Beverloo, 2017-04-11 18:16:38]

+harkness for review
+dtrainor FYI

[harkness, 2017-04-12 10:31:59]

lgtm

[Peter Beverloo, 2017-04-12 16:06:27]

The CQ bit was checked by peter@chromium.org

[commit-bot: I haz the power, 2017-04-12 16:06:55]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-12 19:55:00]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1492013187508550, "parent_rev":
"f93904f5895990201c1e8df1c13352cba68ceb76", "commit_rev":
"0b6bb8eb5aa2c306f7ad88a746bbec775c18b103"}

[commit-bot: I haz the power, 2017-04-12 19:55:55]

Description was changed from

==========
Pass through the response code and headers in Background Fetch

Following this CL, Background Fetch responses will include the response
code and headers as provided by the download manager.

We don't yet support the `backgroundfetchfail` event or handle CORS, but
those can now be implemented in follow-up CLs.

BUG=709489
==========

to

==========
Pass through the response code and headers in Background Fetch

Following this CL, Background Fetch responses will include the response
code and headers as provided by the download manager.

We don't yet support the `backgroundfetchfail` event or handle CORS, but
those can now be implemented in follow-up CLs.

BUG=709489

Review-Url: https://codereview.chromium.org/2814683003
Cr-Commit-Position: refs/heads/master@{#464119}
Committed:
https://chromium.googlesource.com/chromium/src/+/0b6bb8eb5aa2c306f7ad88a746bb...
==========

[commit-bot: I haz the power, 2017-04-12 19:55:56]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/0b6bb8eb5aa2c306f7ad88a746bb...