Revert 222154 "sync: Gracefully handle very early shutdown"

trunk/src/sync/internal_api/public/sync_manager.h

Index: trunk/src/sync/internal_api/public/sync_manager.h
===================================================================
--- trunk/src/sync/internal_api/public/sync_manager.h	(revision 222204)
+++ trunk/src/sync/internal_api/public/sync_manager.h	(working copy)
@@ -45,7 +45,6 @@
 class SyncEncryptionHandler;
 class SyncScheduler;
 struct UserShare;
-class CancelationSignal;
 
 namespace sessions {
 class SyncSessionSnapshot;
@@ -321,8 +320,7 @@
       Encryptor* encryptor,
       scoped_ptr<UnrecoverableErrorHandler> unrecoverable_error_handler,
       ReportUnrecoverableErrorFunction report_unrecoverable_error_function,
-      bool use_oauth2_token,
-      CancelationSignal* cancelation_signal) = 0;
+      bool use_oauth2_token) = 0;
 
   // Throw an unrecoverable error from a transaction (mostly used for
   // testing).
@@ -394,6 +392,17 @@
   // to the syncapi model.
   virtual void SaveChanges() = 0;
 
+  // Initiates shutdown of various components in the sync engine.  Must be
+  // called from the main thread to allow preempting ongoing tasks on the sync
+  // loop (that may be blocked on I/O).  The semantics of |callback| are the
+  // same as with StartConfigurationMode. If provided and a scheduler / sync
+  // loop exists, it will be invoked from the sync loop by the scheduler to
+  // notify that all work has been flushed + cancelled, and it is idle.
+  // If no scheduler exists, the callback is run immediately (from the loop
+  // this was created on, which is the sync loop), as sync is effectively
+  // stopped.
+  virtual void StopSyncingForShutdown() = 0;
+
   // Issue a final SaveChanges, and close sqlite handles.
   virtual void ShutdownOnSyncThread() = 0;