using separate method PacketsQueue::cancelFences for proper synchronization in TilingRenderPolicyXXX destructors

base/fence_manager.cpp

@@ -110,6 +110,9 @@ void FenceManager::cancel()
 {
   threads::MutexGuard g(m_mutex);
 
+  if (m_isCancelled)
+    return;
+
   m_isCancelled = true;
 
   list<pair<int, threads::Condition*> > tempList;

yg/packets_queue.cpp

@@ -93,6 +93,11 @@ namespace yg
       m_fenceManager.cancel();
     }
 
+    void PacketsQueue::cancelFences()
+    {
+      m_fenceManager.cancel();
+    }
+
     void PacketsQueue::processPacket(Packet const & packet)
     {
       if (m_packets.IsCancelled())

yg/packets_queue.hpp

@@ -88,6 +88,7 @@ namespace yg
 
       void processPacket(Packet const & packet);
       void cancel();
+      void cancelFences();
       bool empty() const;
       size_t size() const;