code: function listenToEmberDebugPort(emberDebugPort) {
      // listen for messages from EmberDebug, and pass them on to the background-script
      emberDebugPort.addEventListener('message', function(event) {
        chrome.runtime.sendMessage(event.data);
      });
  
      // listen for messages from the EmberInspector, and pass them on to EmberDebug
      chrome.runtime.onMessage.addListener(function(message) {
        if (message.from === 'devtools') {
          // forward message to EmberDebug
          emberDebugPort.postMessage(message);
        }
      });
  
      emberDebugPort.start();
    }
docs: Listen for messages from EmberDebug.
  @param {Object} emberDebugPort