Warn user in case extension delays network traffic too much.

chrome/browser/resources/options/extension_list.js

 // Copyright (c) 2011 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.
 
 cr.define('options', function() {
   'use strict';
 
   /**
    * A lookup helper function to find the first node that has an id (starting
    * at |node| and going up the parent chain).
@@ skipping 221 matching lines @@
         // Then the optional Visit Website link.
         if (extension.homepageUrl) {
           var link = this.ownerDocument.createElement('a');
           link.classList.add('extension-links-trailing');
           link.textContent =
               localStrings.getString('extensionSettingsVisitWebsite');
           link.href = extension.homepageUrl;
           vbox.appendChild(link);
         }
 
+        if (extension.warnings.length > 0) {
+          var warningsDiv = this.ownerDocument.createElement('div');
+          warningsDiv.classList.add('extension-warnings');
+
+          var warningsHeader = this.ownerDocument.createElement('span');
+          warningsHeader.classList.add('extension-warnings-title');
+          warningsHeader.textContent =
+              localStrings.getString('extensionSettingsWarningsTitle');
+          warningsDiv.appendChild(warningsHeader);
+
+          var warningList = this.ownerDocument.createElement('ul');
+          for (var j = 0; j < extension.warnings.length; ++j) {
+            var warningEntry = this.ownerDocument.createElement('li');
+            warningEntry.textContent = extension.warnings[j];
+            warningList.appendChild(warningEntry);
+          }
+          warningsDiv.appendChild(warningList);
+
+          vbox.appendChild(warningsDiv);
+        }
+
         // And now the details section that is normally hidden.
         var details = this.ownerDocument.createElement('div');
         details.classList.add('vbox');
         vbox.appendChild(details);
 
         this.decorateDetailsSection_(details, extension, expanded, butterbar);
 
         // And on the right of the details we have the Enable/Enabled checkbox.
         div = this.ownerDocument.createElement('div');
         hbox.appendChild(div);
@@ skipping 452 matching lines @@
             String(extension.views[i].renderViewId)
           ]);
         }
       }
     },
   };
 
   return {
     ExtensionsList: ExtensionsList
   };
-});
+});