[Extensions] DCHECK that ExtensionFunctions respond (and only once)

chrome/test/data/extensions/api_test/socket/api/background.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // net/tools/testserver/testserver.py is picky about the format of what it
 // calls its "echo" messages. One might go so far as to mutter to oneself that
 // it isn't an echo server at all.
 //
 // The response is based on the request but obfuscated using a random key.
 const request = "0100000005320000005hello";
@@ skipping 292 matching lines @@
     if (protocol == "tcp")
       chrome.socket.connect(socketId, address, port, onConnect1);
     else
       chrome.socket.bind(socketId, "0.0.0.0", 0, onConnect1);
   }
 
   function onConnect1(result) {
     chrome.test.assertEq(0, result, "failed to connect");
     console.log("Socket connect: result=" + result, chrome.runtime.lastError);
 
-    console.log("calling read with readCB2 callback");
+    console.log("calling read with readCB1 callback");
     if (protocol == "tcp")
       chrome.socket.read(socketId, readCB1);
     else
       chrome.socket.recvFrom(socketId, readCB1);
 
     console.log("calling disconnect");
     chrome.socket.disconnect(socketId);
 
     console.log("calling connect");
     if (protocol == "tcp")
       chrome.socket.connect(socketId, address, port, onConnect2);
     else
       chrome.socket.bind(socketId, "0.0.0.0", 0, onConnect2);
   }
 
   function onConnect2(result) {
     chrome.test.assertEq(0, result, "failed to connect");
     console.log("Socket connect: result=" + result, chrome.runtime.lastError);
 
-    console.log("calling read with readCB1 callback");
+    console.log("calling read with readCB2 callback");
     if (protocol == "tcp")
       chrome.socket.read(socketId, readCB2);
     else
       chrome.socket.recvFrom(socketId, readCB2);
 
     string2ArrayBuffer(request, function (arrayBuffer) {
       if (protocol == "tcp")
         chrome.socket.write(socketId, arrayBuffer, onWriteComplete);
       else
         chrome.socket.sendTo(
             socketId, arrayBuffer, address, port, onWriteComplete);
     });
   }
 
   function onWriteComplete(res) {
     console.log("write callback: bytesWritten=" + res.bytesWritten);
   }
 
   // Callback 1 for initial read call
   function readCB1(readInfo) {
     console.log("Socket read CB1: result=" + readInfo.resultCode,
         chrome.runtime.lastError);
-
-    if (readInfo.resultCode < 0) {
-      chrome.test.fail("Error reading from socket: " + readInfo.resultCode);
-    }
+    // We disconnect the socket right after calling read(), so behavior here
+    // is undefined.
+    // TODO(devlin): Why do we do that? What are we trying to do?
   }
 
   // Second callback, for read call after re-connect
   function readCB2(readInfo) {
     console.log("Socket read CB2: result=" + readInfo.resultCode,
         chrome.runtime.lastError);
     if (readInfo.resultCode === -1) {
       chrome.test.fail("Unable to register a read 2nd callback on the socket!");
     } else if (readInfo.resultCode < 0) {
       chrome.test.fail("Error reading from socket: " + readInfo.resultCode);
@@ skipping 58 matching lines @@
         testSocketCreation,
         testSending,
         testPendingCallback,
         testUsingTCPSocketOnUDPMethods]);
   }
 };
 
 // Find out which protocol we're supposed to test, and which echo server we
 // should be using, then kick off the tests.
 chrome.test.sendMessage("info_please", onMessageReply);