Expose RTT and downlink bandwidth using experimental Javascript API

third_party/WebKit/LayoutTests/fast/dom/Window/resources/window-property-collector.js

 function collectProperties(object, windowHasBeenGCed)
 {
     collectPropertiesHelper(object, object, windowHasBeenGCed, []);
 
     propertiesToVerify.sort(function (a, b)
     {
         if (a.property < b.property)
             return -1
         if (a.property > b.property)
             return 1;
@@ skipping 28 matching lines @@
         return;
 
     // Various special cases for legacy reasons. Please do not add entries to this list.
     var propertyPath = path.join('.');
 
     // Connection type depends on the host, skip.
     if (propertyPath == 'navigator.connection.type')
       return;
     if (propertyPath == 'navigator.connection.downlinkMax')
       return;
+    if (propertyPath == 'navigator.connection.rtt')
+      return;
+    if (propertyPath == 'navigator.connection.downlink')
+      return;
 
     switch (propertyPath) {
     case "location.href":
         expected = "'about:blank'";
         break;
     case "location.origin":
         expected = "'null'";
         break;
     case "origin":
         expected = "'file://'";
@@ skipping 69 matching lines @@
 }
 
 function pathExists(object, path) {
     for (var i = 0; i < path.length; i++) {
         if (!object || !(path[i] in object))
             return false;
         object = object[path[i]];
     }
     return true;
 }