bool PrintWebViewHelper::OnMessageReceived(const IPC::Message& message) {
  bool handled = true;
  IPC_BEGIN_MESSAGE_MAP(PrintWebViewHelper, message)
    IPC_MESSAGE_HANDLER(PrintMsg_PrintPages, OnPrintPages)
    IPC_MESSAGE_HANDLER(PrintMsg_PrintForSystemDialog, OnPrintForSystemDialog)
    IPC_MESSAGE_HANDLER(PrintMsg_InitiatePrintPreview, OnInitiatePrintPreview)
    IPC_MESSAGE_HANDLER(PrintMsg_PrintNodeUnderContextMenu,
                        OnPrintNodeUnderContextMenu)
    IPC_MESSAGE_HANDLER(PrintMsg_PrintPreview, OnPrintPreview)
    IPC_MESSAGE_HANDLER(PrintMsg_PrintForPrintPreview, OnPrintForPrintPreview)
    IPC_MESSAGE_HANDLER(PrintMsg_PrintingDone, OnPrintingDone)
    IPC_MESSAGE_HANDLER(PrintMsg_ResetScriptedPrintCount,
                        ResetScriptedPrintCount)
    IPC_MESSAGE_HANDLER(PrintMsg_PreviewPrintingRequestCancelled,
                        DisplayPrintJobError)
    IPC_MESSAGE_UNHANDLED(handled = false)
    IPC_END_MESSAGE_MAP()
  return handled;
}

Unknown