Don't create parallel request until download file is initialized

Don't create parallel request until download file is initialized

Chrome should wait until download file is initialized before creating parallel requests.
With this CL, it also makes more sense for DownloadJob to own download file.
I will do that in follow up CLs.

BUG=726487
Review-Url: https://codereview.chromium.org/2901383007
Cr-Commit-Position: refs/heads/master@{#475176}
Committed: https://chromium.googlesource.com/chromium/src/+/5555a916120874ae028efea267e9ef7077f1e0df

[qinmin, 2017-05-26 18:08:55]

qinmin@chromium.org changed reviewers:
+ dtrainor@chromium.org, xingliu@chromium.org

[qinmin, 2017-05-26 18:08:56]

PTAL

[qinmin, 2017-05-26 21:10:12]

The CQ bit was checked by qinmin@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-05-26 21:11:05]

Dry run: CQ is trying da patch.

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

[xingliu, 2017-05-26 22:13:48]

lgtm

[commit-bot: I haz the power, 2017-05-26 22:32:42]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2017-05-26 22:32:43]

Dry run: This issue passed the CQ dry run.

[qinmin, 2017-05-26 23:04:31]

The CQ bit was checked by qinmin@chromium.org

[commit-bot: I haz the power, 2017-05-26 23:05:01]

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, 2017-05-26 23:15:48]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1495839871394720, "parent_rev":
"bd089ab97f66fb67dd17b3f6d1862a0922a93f0c", "commit_rev":
"5555a916120874ae028efea267e9ef7077f1e0df"}

[commit-bot: I haz the power, 2017-05-26 23:16:03]

Description was changed from

==========
Don't create parallel request until download file is initialized

Chrome should wait until download file is initialized before creating parallel
requests.
With this CL, it also makes more sense for DownloadJob to own download file.
I will do that in follow up CLs.

BUG=726487
==========

to

==========
Don't create parallel request until download file is initialized

Chrome should wait until download file is initialized before creating parallel
requests.
With this CL, it also makes more sense for DownloadJob to own download file.
I will do that in follow up CLs.

BUG=726487

Review-Url: https://codereview.chromium.org/2901383007
Cr-Commit-Position: refs/heads/master@{#475176}
Committed:
https://chromium.googlesource.com/chromium/src/+/5555a916120874ae028efea267e9...
==========

[commit-bot: I haz the power, 2017-05-26 23:16:04]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/5555a916120874ae028efea267e9...