Make breakpoints not crash sky

sky/framework/inspector/inspector.sky

 <import src="/mojo/public/sky/connection.sky" as="connection" />
 <import src="/mojo/public/sky/core.sky" as="core" />
 <import src="/mojo/public/sky/support.sky" as="support" />
 <import src="/sky/services/inspector/inspector.mojom.sky" as="inspector" />
 <import src="console-agent.sky" as="ConsoleAgent" />
 <import src="dom-agent.sky" as="DOMAgent" />
 <import src="page-agent.sky" as="PageAgent" />
 <import src="worker-agent.sky" as="WorkerAgent" />
 <import src="runtime-agent.sky" as="RuntimeAgent" />
 <import src="indexeddb-agent.sky" as="IndexedDBAgent" />
@@ skipping 64 matching lines @@
 };
 
 InspectorBackend.prototype.onMessage = function(data) {
   var message = JSON.parse(data);
   var result = this.dispatch_(message.method, message.params, message.id);
   this.unansweredMessages_.push(message.id);
   // FIXME: This magic return value is kinda hacky.
   if (result != this.ASYNC_RESPONSE)
     this.sendResponse(message.id, result);
   else {
-    window.setTimeout(function(message_id) {
-      if (this.unansweredMessages_.indexOf(message_id) == -1)
+    window.setTimeout(function() {
+      if (this.unansweredMessages_.indexOf(message.id) == -1)
         return;
-      console.log("Error, failed to reply to " + descriptor
-          + " message id " + message_id);
-    }, this.MESSAGE_TIMEOUT_MS, this, message.id);
+      console.log("Error, failed to reply to message id " + message.id);
+    }.bind(this), this.MESSAGE_TIMEOUT_MS);
   }
 };
 
 InspectorBackend.prototype.sendResponse = function(message_id, result) {
   var messageIndex = this.unansweredMessages_.indexOf(message_id);
   if (messageIndex != -1)
     this.unansweredMessages_.splice(messageIndex, 1);
   else
     console.log("Error, responding to unknown message id " + message_id);
   var response = {
@@ skipping 14 matching lines @@
 
 var frontendHandle = internals.connectToService(
     "mojo:sky_inspector_server", inspector.InspectorFrontend.name);
 window.frontendConnection = new connection.Connection(
     frontendHandle,
     InspectorBackend,
     inspector.InspectorFrontend.proxyClass);
 
 window.frontend = frontendConnection.remote;
 </script>