Fix SpeechUIModel lifetime issue in Chrome's AppListViewDelegate when switching profiles

Fix SpeechUIModel lifetime issue in Chrome's AppListViewDelegate when switching profiles

The AppListView observes the SpeechUIModel directly, so SpeechUIModel
must outlive profile changes within Chrome's AppListViewDelegate.
Profile changes only recreate the app_list::ContentView and subviews,
which updates app_list::AppListModel observers, but not
app_list::SpeechUIModel observers.

This comes up when switching profiles in the desktop app list.

To fix, this change gives SpeechUIModel a default constructor to
simplify setting the initial speech recognition state, which needs the
profile. Then, decouples the lifetime of the SpeechUIModel from the
Profile in Chrome's AppListViewDelegate.

BUG=405827
TBR=jamescook@chromium.org

Committed: https://crrev.com/966607ad9fc89b31dfc991ab65ba941132e2d2bf
Cr-Commit-Position: refs/heads/master@{#293878}

[tapted, 2014-09-08 06:29:55]

tapted@chromium.org changed reviewers:
+ mukai@chromium.org

[tapted, 2014-09-08 06:36:53]

Hi Jun, could you please take a look? There is actually some test coverage
coming in crrev/508813002 but it's a monster patch I need to split up (and
testing chrome/../app_list_view_delegate is super tricky without that monster
patch).

[Jun Mukai, 2014-09-08 16:33:50]

lgtm

[tapted, 2014-09-09 00:06:45]

tapted@chromium.org changed reviewers:
+ jamescook@chromium.org

[tapted, 2014-09-09 00:06:45]

+jamescook TBR for ash/shell/app_list.cc OWNERS (simple refactoring change)

[tapted, 2014-09-09 00:07:18]

The CQ bit was checked by tapted@chromium.org

[commit-bot: I haz the power, 2014-09-09 00:28:50]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/tapted@chromium.org/550883002/20001

[tapted, 2014-09-09 04:56:45]

The CQ bit was unchecked by tapted@chromium.org

[tapted, 2014-09-09 04:57:10]

The CQ bit was checked by tapted@chromium.org

[commit-bot: I haz the power, 2014-09-09 05:00:04]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/tapted@chromium.org/550883002/20001

[commit-bot: I haz the power, 2014-09-09 06:50:25]

Committed patchset #2 (id:20001) as f4c865d9ebf12146f0ef3906ede05e6d73eb5b34

[commit-bot: I haz the power, 2014-09-10 03:51:27]

Patchset 2 (id:??) landed as
https://crrev.com/966607ad9fc89b31dfc991ab65ba941132e2d2bf
Cr-Commit-Position: refs/heads/master@{#293878}