Resubmit: Refactor external_install_ui

Resubmit: Refactor external_install_ui

Third time's the charm.

Previous: https://codereview.chromium.org/309643007/

---------------------------

Refactors ExternalInstallUI to have determinate lifetimes.
This is likely the first of multiple patches targeting this area of code; the
next one will concentrate on pulling the related logic out of ExtensionService.
Adds unittests for accepting/declining external installs.

BUG=378042
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=280067

[Devlin, 2014-06-18 23:48:26]

Hey Yoyo,

I'm hoping it's third time lucky for this one.  Sorry it's taken so much and for
the delay since last time.  Most of the changes should be between Patch Set 1
and 2.

Cheers

[Yoyo Zhou, 2014-06-19 16:59:47]

LGTM

[Devlin, 2014-06-24 16:55:16]

The CQ bit was checked by [email protected]

[commit-bot: I haz the power, 2014-06-24 16:56:18]

CQ is trying da patch. Follow status at

https://chromium-status.appspot.com/cq/[email protected]/315903004/...

[commit-bot: I haz the power, 2014-06-24 21:05:01]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  android_clang_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_clang_dbg/bui...)
  android_dbg on tryserver.chromium
(http://build.chromium.org/p/tryserver.chromium/builders/android_dbg/builds/19...)

[Devlin, 2014-06-24 21:07:51]

The CQ bit was unchecked by [email protected]

[Devlin, 2014-06-26 15:59:14]

The CQ bit was checked by [email protected]

[commit-bot: I haz the power, 2014-06-26 16:00:54]

CQ is trying da patch. Follow status at

https://chromium-status.appspot.com/cq/[email protected]/315903004/...

[commit-bot: I haz the power, 2014-06-26 19:04:01]

Change committed as 280067