[Sync] Fix backup/rollback tests race conditions

[Sync] Fix backup/rollback tests race conditions

The rollback tests now listen to both the ProfileSyncService state as well as
for the completion of the browsing data remover. The shutdown observer now
also listens directly to the ProfileSyncService, rather than polling every
second.

BUG=406005
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=291269

[Nicolas Zea, 2014-08-21 20:28:13]

PTAL. Note that I had to remove the check to see if the backup directory was
deleted as that happens on the sync thread and there's currently no way to
verify when that happens without some significant test-only plumbing.

Additionally, that part should already be covered by normal shutdown testing
logic.

[haitaol1, 2014-08-21 20:50:32]

https://codereview.chromium.org/483883003/diff/1/chrome/browser/sync/test/int...
File chrome/browser/sync/test/integration/single_client_backup_rollback_test.cc
(right):

https://codereview.chromium.org/483883003/diff/1/chrome/browser/sync/test/int...
chrome/browser/sync/test/integration/single_client_backup_rollback_test.cc:431:
SyncRollbackChecker rollback_checker(GetSyncService(0));
You always check rollback and backend shutdown back to back. So why do you need
rollback checker?

[Nicolas Zea, 2014-08-21 20:52:32]

https://codereview.chromium.org/483883003/diff/1/chrome/browser/sync/test/int...
File chrome/browser/sync/test/integration/single_client_backup_rollback_test.cc
(right):

https://codereview.chromium.org/483883003/diff/1/chrome/browser/sync/test/int...
chrome/browser/sync/test/integration/single_client_backup_rollback_test.cc:431:
SyncRollbackChecker rollback_checker(GetSyncService(0));
On 2014/08/21 20:50:32, haitaol1 wrote:
> You always check rollback and backend shutdown back to back. So why do you
need
> rollback checker?

Some of these tests don't require rollback (i.e. the ones with rollback
disabled, or just testing backup).  And it's not enough to check just for IDLE,
as that can happen before rollback completes. So for thoses tests where rollback
is expected, we verify it happens and completes, and only then wait for idle.

[haitaol1, 2014-08-21 21:00:15]

lgtm

[Nicolas Zea, 2014-08-21 21:03:17]

The CQ bit was checked by zea@chromium.org

[commit-bot: I haz the power, 2014-08-21 21:06:34]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/zea@chromium.org/483883003/1

[commit-bot: I haz the power, 2014-08-21 22:19:30]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  android_chromium_gn_compile_rel on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/android_chromiu...)

[commit-bot: I haz the power, 2014-08-22 00:30:17]

Committed patchset #1 (1) as 291269