[Background Sync] Allow sync manager access from uncontrolled clients

[Background Sync] Allow sync manager access from uncontrolled clients

This patch removes the requirement for the caller of a BackgroundSync
manager method to be either a service worker or a controlled client.
Now, uncontrolled clients are also able to access the manager, and Blink
informs the browser whether a registration request came from a Service
Worker or not. (Service Workers are still required to have at least one
active window client in order to register sync events; this is enforced
in the browser).

This is part 1 of a three-part blink-chromium-blink dance.
Part 1: https://codereview.chromium.org/1309393003 (this patch)
Part 2: https://codereview.chromium.org/1316743002
Part 3: https://codereview.chromium.org/1314453003

BUG=518884
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=201230

[iclelland, 2015-08-25 18:45:52]

iclelland@chromium.org changed reviewers:
+ jkarlin@chromium.org

[iclelland, 2015-08-25 18:46:15]

jkarlin: PTAL, thanks!

[jkarlin, 2015-08-26 12:45:41]

lgtm with nit

https://codereview.chromium.org/1309393003/diff/20001/public/platform/modules...
File public/platform/modules/background_sync/WebSyncProvider.h (right):

https://codereview.chromium.org/1309393003/diff/20001/public/platform/modules...
public/platform/modules/background_sync/WebSyncProvider.h:38: //
TODO(iclelland): Remove this deprecated method once callers have switched to the
4-argument version.
The callers have already switched in this case. Perhaps rephrase to "once the
browser implements the 4-argument version".

[iclelland, 2015-08-26 12:54:03]

The CQ bit was checked by iclelland@chromium.org

[iclelland, 2015-08-26 12:54:03]

The patchset sent to the CQ was uploaded after l-g-t-m from jkarlin@chromium.org
Link to the patchset: https://codereview.chromium.org/1309393003/#ps40001
(title: "Fixing comment")

[commit-bot: I haz the power, 2015-08-26 12:54:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1309393003/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1309393003/40001

[commit-bot: I haz the power, 2015-08-26 14:17:54]

Committed patchset #3 (id:40001) as
https://src.chromium.org/viewvc/blink?view=rev&revision=201230

[iclelland, 2015-09-02 17:10:37]

https://codereview.chromium.org/1309393003/diff/20001/public/platform/modules...
File public/platform/modules/background_sync/WebSyncProvider.h (right):

https://codereview.chromium.org/1309393003/diff/20001/public/platform/modules...
public/platform/modules/background_sync/WebSyncProvider.h:38: //
TODO(iclelland): Remove this deprecated method once callers have switched to the
4-argument version.
On 2015/08/26 12:45:41, jkarlin wrote:
> The callers have already switched in this case. Perhaps rephrase to "once the
> browser implements the 4-argument version".

That is, of course, absolutely correct :) Thanks; done.