Revert 244381 "Support GU retry command in sync engine. The comm..."

Test fails on the valgrind bot:
http://build.chromium.org/p/chromium.memory.fyi/builders/Linux%20Tests%20%28tsan%29%281%29/builds/11739/steps/memory%20test%3A%20unit/logs/EphemeralAppServiceTest.RemoveOverflow
EphemeralAppServiceTest.RemoveOverflow: 
../../chrome/browser/apps/ephemeral_app_service_unittest.cc:83: Failure
Value of: removed->first < retained->first
Actual: false
Expected: true

> Support GU retry command in sync engine. The command specifies a delay after which syncer should issue a GU to pick up updates missed by last GU.
> 
> BUG=
> 
> Review URL: https://codereview.chromium.org/124083002

TBR=haitaol@chromium.org

Review URL: https://codereview.chromium.org/135923002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@244438 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 244438