Revert of Restrict transmission of external exp ids to signed in users.

Revert of Restrict transmission of external exp ids to signed in users. (patchset #1 id:1 of https://codereview.chromium.org/2569403003/ )

Reason for revert:
Merge conflict error.

Original issue's description:
> Restrict transmission of external exp ids to signed in users.
> 
> Since external experiment ids are not based on Chrome's low
> entropy source, they do not have the same guarantees about
> not identifying a user as Chrome's variations. As such, we
> should only transmit them for signed in users, whose identity
> is already known by Google so there's no risk of identifying
> them through these headers.
> 
> Note: The signed-in state checking in this CL is only done for
> web content area requests and not other internal requests,
> like to the suggestion service, where it treats the state as
> "not signed in". This is fine to do because variations service
> ids are still sent, which is what the other call sites are
> interested in.
> 
> BUG=672532
> TBR=mpearson@chromium.org,mattm@chromium.org,donnd@chromium.org,afakhry@chromium.org
> 
> Review-Url: https://codereview.chromium.org/2558913003
> Cr-Commit-Position: refs/heads/master@{#437959}
> (cherry picked from commit 9ed7b5611a61505c3dba734fe55b92211df3c2f6)

TBR=afakhry@chromium.org,donnd@chromium.org,mattm@chromium.org,mpearson@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=672532
Review-Url: https://codereview.chromium.org/2576733002

[Alexei Svitkine (slow), 2016-12-14 17:58:03]

The CQ bit was checked by asvitkine@chromium.org

[Alexei Svitkine (slow), 2016-12-14 17:58:03]

Created Revert of Restrict transmission of external exp ids to signed in users.

[commit-bot: I haz the power, 2016-12-14 17:59:03]

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, 2016-12-14 18:03:47]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1481738283378560, "parent_rev":
"ef1bff325b16363dd94b812468be190b039c82e5", "commit_rev":
"13366ed9e79349c270c8ccd9ffd89f7845a8d5b2"}

[commit-bot: I haz the power, 2016-12-14 18:04:24]

Description was changed from

==========
Revert of Restrict transmission of external exp ids to signed in users.
(patchset #1 id:1 of https://codereview.chromium.org/2569403003/ )

Reason for revert:
Merge conflict error.

Original issue's description:
> Restrict transmission of external exp ids to signed in users.
> 
> Since external experiment ids are not based on Chrome's low
> entropy source, they do not have the same guarantees about
> not identifying a user as Chrome's variations. As such, we
> should only transmit them for signed in users, whose identity
> is already known by Google so there's no risk of identifying
> them through these headers.
> 
> Note: The signed-in state checking in this CL is only done for
> web content area requests and not other internal requests,
> like to the suggestion service, where it treats the state as
> "not signed in". This is fine to do because variations service
> ids are still sent, which is what the other call sites are
> interested in.
> 
> BUG=672532
>
TBR=mpearson@chromium.org,mattm@chromium.org,donnd@chromium.org,afakhry@chrom...
> 
> Review-Url: https://codereview.chromium.org/2558913003
> Cr-Commit-Position: refs/heads/master@{#437959}
> (cherry picked from commit 9ed7b5611a61505c3dba734fe55b92211df3c2f6)

TBR=afakhry@chromium.org,donnd@chromium.org,mattm@chromium.org,mpearson@chrom...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=672532
==========

to

==========
Revert of Restrict transmission of external exp ids to signed in users.
(patchset #1 id:1 of https://codereview.chromium.org/2569403003/ )

Reason for revert:
Merge conflict error.

Original issue's description:
> Restrict transmission of external exp ids to signed in users.
> 
> Since external experiment ids are not based on Chrome's low
> entropy source, they do not have the same guarantees about
> not identifying a user as Chrome's variations. As such, we
> should only transmit them for signed in users, whose identity
> is already known by Google so there's no risk of identifying
> them through these headers.
> 
> Note: The signed-in state checking in this CL is only done for
> web content area requests and not other internal requests,
> like to the suggestion service, where it treats the state as
> "not signed in". This is fine to do because variations service
> ids are still sent, which is what the other call sites are
> interested in.
> 
> BUG=672532
>
TBR=mpearson@chromium.org,mattm@chromium.org,donnd@chromium.org,afakhry@chrom...
> 
> Review-Url: https://codereview.chromium.org/2558913003
> Cr-Commit-Position: refs/heads/master@{#437959}
> (cherry picked from commit 9ed7b5611a61505c3dba734fe55b92211df3c2f6)

TBR=afakhry@chromium.org,donnd@chromium.org,mattm@chromium.org,mpearson@chrom...
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=672532

Review-Url: https://codereview.chromium.org/2576733002
==========

[commit-bot: I haz the power, 2016-12-14 18:04:25]

Committed patchset #1 (id:1)