Problems using remote debugging protocol in Google Chrome extension - google-chrome-extension

Question

I am developing my own implementation of DevMode for GWT-like framework. This DevMode is to
work like GWT's old DevMode, which is going to be deprecated, since GWT teavm doesn't want to
support browser plugins. Another reason is NPAPI was removed from latest versions of Google Chrome.
So my DevMode implementation has its own Google Chrome extension, which is written completely in
JavaScript and communicates with server through WebSocket.
The main goal of DevMode is to enable debugging of Java code in Java IDE. It runs Java code
in JVM, and when JVM attempts to execute JavaScript code, it transfers it remotely to browser
extension, which executes JavaScript and sends result back. However, thing are slightly more
difficult in practice, as JVM can pass callback to JavaScript, so there is bi-directional
message flow between JVM and browser extension, in any depth of nesting. Consider the following
ping-pong:
public class PingPong {
public native void ping(int count) /*-{
console.log("Before ping %d", count);
this.pong(count - 1);
console.log("After ping %d", count);
-}*/;
public void pong(int count) {
System.out.println("Before pong " + count);
ping(count - 1);
System.out.println("After pong " + count);
}
}
When ping calls pong it should wait until JVM receives message, handles it and sends response
back. Furthermore, JVM calls ping again and so forth. However, WebSocket API is asynchronous.
Also, we can't just block until JVM responds, as JVM may call JavaScript again.
So I use remote debugging protocol in my extension.
When extension receives a command to call a JavaScript method,
it sends the Runtime.callFunctionOn command to debugger API. When Java passes callback to
extension, it creates the following proxy function:
function() {
var params = [];
for (var i = 0; i < arguments.length; ++i) {
params.push(arguments[i]);
}
return sendMessage({
type : "invoke-method",
methodName : methodName,
args : params
});
}
where sendMessage is:
function sendMessage(message) {
sentMessage = message;
while (sentMessage != null) {
debugger;
}
return receivedMessage;
}
Further, extension listens to the Debugger.paused notification. When a notification comes,
extension sends message to JVM and waits for response. After response is received,
extension sets receivedMessage, clears sentMessage and sends Debugger.resume to debugger.
Unfortunately, I have two major problems. First, I when call
element.addEventListener("click", callback)
from JVM, and then click the element, Debugger.paused comes as expected.
But when I read sentMessage through RDP, I get objectId different from that I passed to
addEventListener. Are objects ids persistent in Google Chrome debugger API?
Second problem is speed. RDP roundtrip takes 10-20 milliseconds on each call. Is there another
way to block execution of script using Google Chrome extension APIs? Also, I want not only
to block, but to enter a nested event loop, since JVM callback may call JavaScript again.