Revert 239676 "[GCM] Delay running register/send operations when..."
The CL has caused use-after-free reports on Valgrind bots.

> [GCM] Delay running register/send operations when loading is in progress
> 
> When GCMProfileService and GCMClient are loading from persistent stores,
> we need to delay register/send operations until the loading is all done.
> 
> A new inner class DelayedTaskController has been added to GCMProfileService.
> 
> Also, GCMClient interface has been updated to add a new method SetDelegate
> that should be called to passs the delegate for a given user. We used to
> rely on passing delegate in CheckIn. But it is not always called because
> the check-in info could be loaded directly from the prefs store.
> 
> BUG=284553
> TEST=existing tests plus new tests added
> 
> Review URL: https://codereview.chromium.org/103933004

TBR=jianli@chromium.org

Review URL: https://codereview.chromium.org/98353005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@239750 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 239750