private void invalidateSurfaces(){
  validSrcDataRef.clear();
  validDstDataRef.clear();
}

private void invalidateSurfaces ( ) { validSrcDataRef . clear ( ) ; validDstDataRef . clear ( ) ; }
invalidates the surfaces associated with this context . this is useful when the context is no longer needed , and we want to break the chain caused by these surface references . note : must be called while the renderqueue lock is held .
