Revert of [XMLHttpRequest] Stop throwing for network error in async mode

LayoutTests/fast/files/workers/resources/worker-apply-blob-url-to-xhr.js

+function log(message)
+{
+    postMessage(message);
+}
+
+function sendXMLHttpRequest(method, url)
+{
+    var xhr = new XMLHttpRequest();
+    xhr.open(method, url, false);
+    try {
+        xhr.send();
+        log("Status: " + xhr.status);
+        log("Response: " + xhr.responseText);
+    } catch (error) {
+        log("Received exception, code: " + error.code + ", name: " + error.name + ", message: " + error.message);
+    }
+}
+
+onmessage = function(event)
+{
+    var file = event.data;
+    var fileURL = URL.createObjectURL(file);
+
+    log("Test that XMLHttpRequest GET succeeds.");
+    sendXMLHttpRequest("GET", fileURL);
+
+    log("Test that XMLHttpRequest POST fails.");
+    xhr = new XMLHttpRequest();
+    sendXMLHttpRequest("POST", fileURL);
+
+    log("Test that XMLHttpRequest GET fails after the blob URL is revoked.");
+    URL.revokeObjectURL(fileURL);
+    sendXMLHttpRequest("GET", fileURL);
+
+    log("DONE");
+}