Fix UserSessionManager::Shutdown ordering.

Fix UserSessionManager::Shutdown ordering.

UserSessionManager::Shutdown calls ~TokenHandleFetcher.
~TokenHandleFetcher sometimes calls ProfileOAuth2TokenService when there's a
pending request.
ProfileOAuth2TokenService is a profile KeyedService that gets deleted when
ProfileImpls are deleted.
ProfileImpls are owned by ProfileManager, which is owned by BrowserProcess,
and these get deleted in BrowserProcessImpl::StartTearDown, which is called
by ChromeBrowserMainParts::PostMainMessageLoopRun.

Hence UserSessionManager::Shutdown must be called before PostMainMessageLoopRun,
otherwise we have crashes when UserSessionManager::token_handle_fetcher_
is not null, and there are pending refresh token requests.

BUG=510997
Committed: https://crrev.com/ceda654bae23888a8489fd46d46cdb7a8d8fe6b9
Cr-Commit-Position: refs/heads/master@{#343318}

[achuithb, 2015-08-14 00:18:31]

achuith@chromium.org changed reviewers:
+ xiyuan@chromium.org

[achuithb, 2015-08-14 00:18:31]

Xiyuan, what do you think?

[achuithb, 2015-08-14 00:21:27]

achuith@chromium.org changed reviewers:
+ antrim@chromium.org

[achuithb, 2015-08-14 00:21:27]

Denis for FYI, seems to be OOO

[xiyuan, 2015-08-14 01:01:50]

lgtm

[achuithb, 2015-08-14 01:19:44]

On 2015/08/14 01:01:50, xiyuan wrote:
> lgtm

Ty

[achuithb, 2015-08-14 01:19:50]

The CQ bit was checked by achuith@chromium.org

[commit-bot: I haz the power, 2015-08-14 01:20:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1285363003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1285363003/1

[commit-bot: I haz the power, 2015-08-14 02:00:20]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-14 02:00:54]

Patchset 1 (id:??) landed as
https://crrev.com/ceda654bae23888a8489fd46d46cdb7a8d8fe6b9
Cr-Commit-Position: refs/heads/master@{#343318}

[achuithb, 2015-08-14 19:30:10]

achuith@chromium.org changed reviewers:
+ ihf@chromium.org

[achuithb, 2015-08-14 19:30:10]

+Ilja for fyi