Sort headers for iteration

third_party/WebKit/LayoutTests/http/tests/fetch/script-tests/headers.js

 if (self.importScripts) {
   importScripts('../resources/fetch-test-helpers.js');
 }
 
 test(function() {
     var expectedValueMap = {
       'content-language': 'ja',
       'content-type': 'text/html; charset=UTF-8',
       'x-fetch-test': 'response test field'
     };
@@ skipping 203 matching lines @@
                   function() { var headers = new Headers([['a', 'b'], []]); },
                   'new Headers with a sequence with less than two strings ' +
                   'should throw');
     assert_throws({name: 'TypeError'},
                   function() { var headers = new Headers([['a', 'b'],
                                                           ['x', 'y', 'z']]); },
                   'new Headers with a sequence with more than two strings ' +
                   'should throw');
   }, 'Headers');
 
+test(function(t) {
+    const headers = new Headers;
+    headers.set('b', '1');
+    headers.set('c', '2');
+    headers.set('a', '3');
+
+    const keys = [];
+    for (let [key, value] of headers)
+        keys.push(key);
+    assert_array_equals(keys, ['a', 'b', 'c'],
+                        'The pairs to iterate over should be sorted.');
+}, 'Iteration order');
+
+test(function(t) {
+    const headers = new Headers;
+    headers.set('a', '1');
+    headers.set('b', '2');
+    headers.set('c', '3');
+
+    const iterator = headers.entries();
+
+    headers.delete('a');
+    headers.set('d', '4');
+
+    const keys = [];
+    for (let [key, value] of iterator)
+        keys.push(key);
+    assert_array_equals(keys, ['a', 'b', 'c'],
+                        'The pairs to iterate over should be the return ' +
+                        'value of an algorithm that implicitly makes a copy.');
+}, 'Iteration mutation');
+
 done();