Reland of This CL replaces e-mail with AccountId on user selection screen.

Reland of This CL replaces e-mail with AccountId on user selection screen. (patchset #1 id:1 of https://codereview.chromium.org/1454153002/ )

Reason for revert:
This did not fix issues, reverting the revert.

Original issue's description:
> Revert of This CL replaces e-mail with AccountId on user selection screen. (patchset #12 id:220001 of https://codereview.chromium.org/1440583002/ )
>
> Reason for revert:
> Suspecting this CL for introducing failures on Mac 10.10 Release (ATI)
>
> First failure: https://build.chromium.org/p/chromium.gpu/builders/Mac%2010.10%20Release%20%28ATI%29/builds/8148
>
> Failing tests:
> CastStreamingApiTestWithPixelOutput.EndToEnd
> TabCaptureApiPixelTest.EndToEndThroughWebRTC
> TabCaptureApiPixelTest.EndToEndWithoutRemoting
>
> Please update tests.
>
> Original issue's description:
> > This CL replaces e-mail with AccountId on user selection screen.
> >
> > This CL replaces e-mail with serialized AccountId on user selection screen.
> > It also adds simple AccountId Serialize/Deserialize methods suitable for
> > passing AccountId to JS code.
> >
> > This is part of transition to AccountId.
> >
> > BUG=462823, 552034
> > TEST=manual
> >
> > Committed: https://crrev.com/1e24fe57a4ca921355bb1506f5a79627647a8c16
> > Cr-Commit-Position: refs/heads/master@{#360319}
>
> TBR=dzhioev@chromium.org,rogerta@chromium.org,stevenjb@chromium.org,oshima@chromium.org,alemate@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=462823, 552034
>
> Committed: https://crrev.com/dede4c3836de2dddda5a484f098bba7152a6779b
> Cr-Commit-Position: refs/heads/master@{#360369}

TBR=dzhioev@chromium.org,rogerta@chromium.org,stevenjb@chromium.org,oshima@chromium.org,alemate@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=462823, 552034
Committed: https://crrev.com/b1723ed336199cc11039ca4a2746e20a7ebc3e9a
Cr-Commit-Position: refs/heads/master@{#360423}

[hcarmona, 2015-11-18 21:48:40]

Created Reland of This CL replaces e-mail with AccountId on user selection
screen.

[commit-bot: I haz the power, 2015-11-18 21:50:32]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1455263002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1455263002/1

[commit-bot: I haz the power, 2015-11-18 21:53:05]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-18 21:53:53]

Patchset 1 (id:??) landed as
https://crrev.com/b1723ed336199cc11039ca4a2746e20a7ebc3e9a
Cr-Commit-Position: refs/heads/master@{#360423}