text: Title: How to use sb_cdp to solve cross-origin iframe
  Body: Blocked a frame with origin "file://" from accessing a cross-origin frame
  
  Refer to the following code:
  https://gist.github.com/imaman/cd7c943e0831a447b1d2b073ede347e2
  
  ```js
  async function findElementInCrossDomainIframe(port, DOM, Target, iframeSelector, elementSelector) {
  
      const doc = await DOM.getDocument({depth: 1});
      const iframeQueryResult = await DOM.querySelector({nodeId: doc.root.nodeId, selector: iframeSelector});    
      const iframeDescription = await DOM.describeNode({nodeId: iframeQueryResult.nodeId});
      if (iframeDescription.node.contentDocument) {
          throw new Error('oops. probably same domain');
      }
  
      // This call is important. Without it, the creation of a new CDP which attached to the iframe
      // (as its target) will fail.
      await Target.getTargets();
      let client2;    
      try {
          client2 = await CDP({port, target: iframeDescription.node.frameId});
          const DOM2 = client2.DOM;
  
          const doc2 = await DOM2.getDocument({depth: 1});
          const elementQueryResult = await DOM2.querySelector({nodeId: doc2.root.nodeId, selector: elementSelector});
          return await DOM2.describeNode({nodeId: elementQueryResult.nodeId});    
      } finally {
          if (client2) {
              client2.close();
          }
      }
  }
  ```