Revert of Inline sign in extracts gaia id from HTTP header and seeds account tracker

Revert of Inline sign in extracts gaia id from HTTP header and seeds account tracker (patchset #46 id:1740001 of https://codereview.chromium.org/473153002/)

Reason for revert:
This breaks Chrome OS GAIA login.

After successful GAIA authentication uses sees blank white page and nothing happens.

Please build chromeos=1 build and check that sign in as new user works fine before relanding this CL. Unfortunately autotests rely on fake gaia server and doesn't check this end-to-end sign in flow.

Original issue's description:
> Inline login handler extracts gaia id from HTTP header and seeds account tracker
> service during sign in.
>
> BUG=341408
>
> Committed: https://crrev.com/a8e7c94b1b79a0948d05a1fcfff53391d22ce37a
> Cr-Commit-Position: refs/heads/master@{#300750}

TBR=guohui@chromium.org,bartfab@chromium.org,xiyuan@chromium.org,achuith@chromium.org,davemoore@chromium.org,rogerta@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=341408
Committed: https://crrev.com/bbaf207927765f4b7c7cae2a4af8db6c4c4a67ce
Cr-Commit-Position: refs/heads/master@{#300873}

[Nikita (slow), 2014-10-23 11:51:12]

Created Revert of Inline sign in extracts gaia id from HTTP header and seeds
account tracker

[commit-bot: I haz the power, 2014-10-23 11:52:24]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/671183002/1

[commit-bot: I haz the power, 2014-10-23 11:53:12]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-23 11:53:59]

Patchset 1 (id:??) landed as
https://crrev.com/bbaf207927765f4b7c7cae2a4af8db6c4c4a67ce
Cr-Commit-Position: refs/heads/master@{#300873}

[bartfab (slow), 2014-10-23 11:56:00]

Bummer. I expect that the fix will be something trivial.

Until then, reverting is the only option. LGTM.

[Nikita (slow), 2014-10-23 11:57:52]

On 2014/10/23 11:56:00, bartfab wrote:
> Bummer. I expect that the fix will be something trivial.

Yes, I suspect it is most likely has to be removal of extension success
endpoint.

> Until then, reverting is the only option. LGTM.

[Nikita (slow), 2014-10-24 14:34:28]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/677703002/ by nkostylev@chromium.org.

The reason for reverting is: White success page and no way to proceed only
reproduces for use_athena=1 builds.

This CL fixes that: https://codereview.chromium.org/642693003/

Re-landing..