Remove unnecessary logic from UpdateScreen

Remove unnecessary logic from UpdateScreen

This logic was added in an attempt to resolve incompatibilities
with autoupdate_EndToEndTest, but it was not successful.
This commit is mainly a revert of https://codereview.chromium.org/2894783003/
However, it preserves some useful functionality such as unit tests.

BUG=chromium:710716
BUG=b:34385702
TEST=unit test

Review-Url: https://codereview.chromium.org/2952083002
Cr-Commit-Position: refs/heads/master@{#481603}
Committed: https://chromium.googlesource.com/chromium/src/+/4b80b10f3323a5d0d6a716f1b57c79559419ff31

[kumarniranjan, 2017-06-21 23:50:12]

kumarniranjan@google.com changed reviewers:
+ xiyuan@chromium.org

[kumarniranjan, 2017-06-21 23:50:13]

Hi Xiyuan,

This is the new CL which had to be uploaded because I had to do some rebasing. I
also took this opportunity to preserve some parts of the previous CL which are
useful (e.g. unit tests of UpdateScreen)

[xiyuan, 2017-06-22 16:49:16]

lgtm

[kumarniranjan, 2017-06-22 16:50:16]

The CQ bit was checked by kumarniranjan@google.com

[commit-bot: I haz the power, 2017-06-22 16:50:39]

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, 2017-06-22 18:06:31]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1498150216485580, "parent_rev":
"066f992488dd298b4af581f56283a2f7d2ddbe6f", "commit_rev":
"4b80b10f3323a5d0d6a716f1b57c79559419ff31"}

[commit-bot: I haz the power, 2017-06-22 18:06:47]

Description was changed from

==========
Remove unnecessary logic from UpdateScreen

This logic was added in an attempt to resolve incompatibilities
with autoupdate_EndToEndTest, but it was not successful.
This commit is mainly a revert of https://codereview.chromium.org/2894783003/
However, it preserves some useful functionality such as unit tests.

BUG=chromium:710716
BUG=b:34385702
TEST=unit test
==========

to

==========
Remove unnecessary logic from UpdateScreen

This logic was added in an attempt to resolve incompatibilities
with autoupdate_EndToEndTest, but it was not successful.
This commit is mainly a revert of https://codereview.chromium.org/2894783003/
However, it preserves some useful functionality such as unit tests.

BUG=chromium:710716
BUG=b:34385702
TEST=unit test

Review-Url: https://codereview.chromium.org/2952083002
Cr-Commit-Position: refs/heads/master@{#481603}
Committed:
https://chromium.googlesource.com/chromium/src/+/4b80b10f3323a5d0d6a716f1b57c...
==========

[commit-bot: I haz the power, 2017-06-22 18:06:51]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/4b80b10f3323a5d0d6a716f1b57c...