[Sync] Refactoring polling to be reliable.

chrome/browser/sync/glue/sync_backend_host_core.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/sync/glue/sync_backend_host_core.h"
 
 #include "base/files/file_util.h"
 #include "base/metrics/histogram.h"
 #include "chrome/browser/sync/glue/invalidation_adapter.h"
 #include "chrome/browser/sync/glue/local_device_info_provider_impl.h"
@@ skipping 439 matching lines @@
   // UpdateCredentials can be called during backend initialization, possibly
   // when backend initialization has failed but hasn't notified the UI thread
   // yet. In that case, the sync manager may have been destroyed on the sync
   // thread before this task was executed, so we do nothing.
   if (sync_manager_) {
     sync_manager_->UpdateCredentials(credentials);
   }
 }
 
 void SyncBackendHostCore::DoStartSyncing(
-    const syncer::ModelSafeRoutingInfo& routing_info) {
+    const syncer::ModelSafeRoutingInfo& routing_info,
+    base::Time last_poll_time) {
   DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
-  sync_manager_->StartSyncingNormally(routing_info);
+  sync_manager_->StartSyncingNormally(routing_info, last_poll_time);
 }
 
 void SyncBackendHostCore::DoSetEncryptionPassphrase(
     const std::string& passphrase,
     bool is_explicit) {
   DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   sync_manager_->GetEncryptionHandler()->SetEncryptionPassphrase(
       passphrase, is_explicit);
 }
 
@@ skipping 249 matching lines @@
       base::TimeDelta::FromSeconds(kSaveChangesIntervalSeconds),
       this, &SyncBackendHostCore::SaveChanges);
 }
 
 void SyncBackendHostCore::SaveChanges() {
   DCHECK_EQ(base::MessageLoop::current(), sync_loop_);
   sync_manager_->SaveChanges();
 }
 
 }  // namespace browser_sync