title: how to check the console.log output of devtools source code in chrome
body: <p>Have anyone known where is the output of console.log in the InspectorBackend.js of devtools code. I found the console panel in the chrome have no any output.</p>
  
  <p>for example, I have set dumpInspectorProtocolMessages = true, and and also add console.error in the function _wrapCallbackAndSendMessageObject as following: </p>
  
  <pre><code>   console.error("show error on console");
     if (this.dumpInspectorProtocolMessages)
          console.log("frontend: " + JSON.stringify(messageObject));
  </code></pre>
  
  <p>I think the console panel in the chrome was loaded after above function, so where is the output, how to check it? </p>
  
  <p>Btw, the function above is devtools source code, and what i want to see is the log output of devtools source code.</p>
  
  <p>thanks</p>