Signin: Reuse existing "update gms" dialogs when possible.

Signin: Reuse existing "update gms" dialogs when possible.

Currently, |updateAccounts()| is sometimes called multiple times in
AccountSigninView which results in multiple "update GMS" dialogs being
generated, and the user must click back three times for the dialogs to
disappear.

This CL changes signin to re-use existing dialogs where possible and
always remove old dialogs before creating a new one.

BUG=679851
Review-Url: https://codereview.chromium.org/2626083004
Cr-Commit-Position: refs/heads/master@{#443349}
(cherry picked from commit 5a7ffae71d0dcf646d26ef202f8d1882587724c7)

Review-Url: https://codereview.chromium.org/2643373002 .
Cr-Commit-Position: refs/branch-heads/2924@{#827}
Cr-Branched-From: 3a87aecc31cd1ffe751dd72c04e5a96a1fc8108a-refs/heads/master@{#433059}
Committed: https://chromium.googlesource.com/chromium/src/+/0851a76d19a01b08e8d65122a12a7a384ca8b91c

[estevenson, 2017-01-20 23:47:33]

Description was changed from

==========
Signin: Reuse existing "update gms" dialogs when possible.

Currently, |updateAccounts()| is sometimes called multiple times in
AccountSigninView which results in multiple "update GMS" dialogs being
generated, and the user must click back three times for the dialogs to
disappear.

This CL changes signin to re-use existing dialogs where possible and
always remove old dialogs before creating a new one.

BUG=679851

Review-Url: https://codereview.chromium.org/2626083004
Cr-Commit-Position: refs/heads/master@{#443349}
(cherry picked from commit 5a7ffae71d0dcf646d26ef202f8d1882587724c7)
==========

to

==========
Signin: Reuse existing "update gms" dialogs when possible.

Currently, |updateAccounts()| is sometimes called multiple times in
AccountSigninView which results in multiple "update GMS" dialogs being
generated, and the user must click back three times for the dialogs to
disappear.

This CL changes signin to re-use existing dialogs where possible and
always remove old dialogs before creating a new one.

BUG=679851

Review-Url: https://codereview.chromium.org/2626083004
Cr-Commit-Position: refs/heads/master@{#443349}
(cherry picked from commit 5a7ffae71d0dcf646d26ef202f8d1882587724c7)

Review-Url: https://codereview.chromium.org/2643373002 .
Cr-Commit-Position: refs/branch-heads/2924@{#827}
Cr-Branched-From:
3a87aecc31cd1ffe751dd72c04e5a96a1fc8108a-refs/heads/master@{#433059}
Committed:
https://chromium.googlesource.com/chromium/src/+/0851a76d19a01b08e8d65122a12a...
==========

[estevenson, 2017-01-20 23:47:34]

Committed patchset #1 (id:1) manually as
0851a76d19a01b08e8d65122a12a7a384ca8b91c.