Revert 164565 - sync: make scheduling logic and job ownership more obvious.

sync/engine/syncer.h

Index: sync/engine/syncer.h
===================================================================
--- sync/engine/syncer.h	(revision 164641)
+++ sync/engine/syncer.h	(working copy)
@@ -57,9 +57,7 @@
   void RequestEarlyExit();
 
   // Runs a sync cycle from |first_step| to |last_step|.
-  // Returns true if the cycle completed with |last_step|, and false
-  // if it terminated early due to error / exit requested.
-  virtual bool SyncShare(sessions::SyncSession* session,
+  virtual void SyncShare(sessions::SyncSession* session,
                          SyncerStep first_step,
                          SyncerStep last_step);