[SyncFS] Refine SyncProcessRunner's throttling algorithm for parallel task support

chrome/browser/sync_file_system/sync_file_system_service.cc

Index: chrome/browser/sync_file_system/sync_file_system_service.cc
diff --git a/chrome/browser/sync_file_system/sync_file_system_service.cc b/chrome/browser/sync_file_system/sync_file_system_service.cc
index 20bec892c5a89a0668fd17ac4ec045d0cb55f2a7..bbbd28930f85f1468ee989a5d7918938abacbd82 100644
--- a/chrome/browser/sync_file_system/sync_file_system_service.cc
+++ b/chrome/browser/sync_file_system/sync_file_system_service.cc
@@ -161,8 +161,7 @@ class LocalSyncRunner : public SyncProcessRunner,
     OnChangesUpdated(pending_changes);
 
     // Kick other sync runners just in case they're not running.
-    GetSyncService()->RunForEachSyncRunners(
-        &SyncProcessRunner::ScheduleIfNotRunning);
+    GetSyncService()->RunForEachSyncRunners(&SyncProcessRunner::Schedule);
   }
 
  private:
@@ -211,8 +210,7 @@ class RemoteSyncRunner : public SyncProcessRunner,
     OnChangesUpdated(pending_changes);
 
     // Kick other sync runners just in case they're not running.
-    GetSyncService()->RunForEachSyncRunners(
-        &SyncProcessRunner::ScheduleIfNotRunning);
+    GetSyncService()->RunForEachSyncRunners(&SyncProcessRunner::Schedule);
   }
 
   virtual void OnRemoteServiceStateUpdated(