qtools_profiler-8.x-1.x-dev/react-app/chrome-extension/content-script.js

/**
 * Listen for outgoing messages.
 */
window.addEventListener('message', function(event) {

  // Only accept messages from same frame.
  if (event.source !== window) {
    return;
  }

  var message = event.data;

  // Only accept messages of correct format (our messages)
  if (typeof message !== 'object' || message === null ||
      !message.inspector || message.source !== 'preview') {
    return;
  }

  chrome.runtime.sendMessage({data: message});
});