DevTools: simplify http handler delegate as it is moving into content.

chrome/test/data/devtools/target_list/background.js

 // Copyright (c) 2013 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.
 
 var REMOTE_DEBUGGER_HOST = 'localhost:9222';
 
 function requestUrl(path, callback) {
   var req = new XMLHttpRequest();
   req.open('GET', 'http://' + REMOTE_DEBUGGER_HOST + path, true);
   req.onload = function() {
@@ skipping 17 matching lines @@
 
   var wsAddress = REMOTE_DEBUGGER_HOST + '/devtools/page/' + target.id;
 
   chrome.test.assertEq(
       '/devtools/inspector.html?ws=' + wsAddress,
       target.devtoolsFrontendUrl);
   // On some platforms (e.g. Chrome OS) target.faviconUrl might be empty for
   // a freshly created tab. Ignore the check then.
   if (target.faviconUrl && opt_faviconUrl)
     chrome.test.assertEq(opt_faviconUrl, target.faviconUrl);
-  // Sometimes thumbnailUrl is not available for a freshly loaded tab.
-  if (target.thumbnailUrl)
-    chrome.test.assertEq('/thumb/' + target.id, target.thumbnailUrl);
   chrome.test.assertEq(opt_title || target.url, target.title);
   chrome.test.assertEq(type, target.type);
   chrome.test.assertEq('ws://' + wsAddress, target.webSocketDebuggerUrl);
 
   return target;
 }
 
 function waitForTab(filter, callback) {
   var fired = false;
   function onUpdated(updatedTabId, changeInfo, updatedTab) {
@@ skipping 191 matching lines @@
   },
 
   function newSpecificPage() {
     runNewPageTest('/json/new?chrome://version/', "chrome://version/");
   },
 
   function newDefaultPage() {
     runNewPageTest('/json/new', "about:blank");
   }
 ]);