Reland of https://codereview.chromium.org/13891016/. This includes the fix for the Segfault on Chro…

chrome/browser/sync_file_system/drive_file_sync_service.h

Index: chrome/browser/sync_file_system/drive_file_sync_service.h
diff --git a/chrome/browser/sync_file_system/drive_file_sync_service.h b/chrome/browser/sync_file_system/drive_file_sync_service.h
index 6bab9baa4f641f53b784c78a81105bb3762062b4..4feb471bc1ec3eae1180ccf344301750ed18f151 100644
--- a/chrome/browser/sync_file_system/drive_file_sync_service.h
+++ b/chrome/browser/sync_file_system/drive_file_sync_service.h
@@ -11,12 +11,11 @@
 #include <string>
 #include <vector>
 
-#include "base/callback_forward.h"
+#include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
 #include "base/threading/non_thread_safe.h"
-#include "base/timer.h"
 #include "chrome/browser/google_apis/drive_notification_observer.h"
 #include "chrome/browser/sync_file_system/drive_file_sync_client_interface.h"
 #include "chrome/browser/sync_file_system/drive_metadata_store.h"
@@ -112,7 +111,7 @@ class DriveFileSyncService
   virtual void OnNetworkConnected() OVERRIDE;
 
   // google_apis::DriveNotificationObserver implementation.
-  virtual void CheckForUpdates() OVERRIDE;
+  virtual void OnNotificationReceived() OVERRIDE;
 
  private:
   friend class DriveFileSyncServiceMockTest;
@@ -444,9 +443,6 @@ class DriveFileSyncService
       google_apis::GDataErrorCode error,
       scoped_ptr<google_apis::ResourceList> changes);
   bool GetOriginForEntry(const google_apis::ResourceEntry& entry, GURL* origin);
-  void SchedulePolling();
-  void OnPollingTimerFired();
-  void UpdatePollingDelay(int64 new_delay_sec);
   void NotifyObserversFileStatusChanged(const fileapi::FileSystemURL& url,
                                         SyncFileStatus sync_status,
                                         SyncAction action_taken,
@@ -508,11 +504,6 @@ class DriveFileSyncService
   // NotifyTaskDone when the task finished.
   scoped_ptr<TaskToken> token_;
 
-  // Timer to trigger fetching changes for incremental sync.
-  base::OneShotTimer<DriveFileSyncService> polling_timer_;
-  // If polling_delay_seconds_ is negative (<0) the timer won't start.
-  int64 polling_delay_seconds_;
-
   // Is set to true when there's a fair possibility that we have some
   // remote changes that haven't been fetched yet.
   //