Revert of [ServiceWorker] Make Response class better conformance with the spec.

LayoutTests/http/tests/serviceworker/resources/headermap-worker.js

+importScripts('worker-test-helpers.js');
+
+test(function() {
+    var expectedMap = {
+        'Content-Language': 'ja',
+        'Content-Type': 'text/html; charset=UTF-8',
+        'X-ServiceWorker-Test': 'response test field'
+    };
+
+    var headers = new HeaderMap;
+    Object.keys(expectedMap).forEach(function(key) {
+        headers.set(key, expectedMap[key]);
+    });
+
+    // 'size'
+    assert_equals(headers.size, 3, 'headers.size should match');
+
+    // 'has()', 'get()'
+    var key = 'Content-Type';
+    assert_true(headers.has(key));
+    assert_equals(headers.get(key), expectedMap[key]);
+
+    // 'delete()'
+    var deleteKey = 'Content-Type';
+    headers.delete(deleteKey);
+    assert_equals(headers.size, 2, 'headers.size should have -1 size');
+    Object.keys(expectedMap).forEach(function(key) {
+        if (key == deleteKey)
+            assert_false(headers.has(key));
+        else
+            assert_true(headers.has(key));
+    });
+
+    // 'set()'
+    var testCasesForSet = [
+        // For a new key/value pair.
+        { key: 'Cache-Control',
+          value: 'max-age=3600',
+          isNewEntry: true },
+
+        // For an existing key.
+        { key: 'X-ServiceWorker-Test',
+          value: 'response test field - updated',
+          isUpdate: true },
+
+        // For setting a numeric value, expecting to see DOMString on getting.
+        { key: 'X-Numeric-Value',
+          value: 12345,
+          expectedValue: '12345',
+          isNewEntry: true },
+
+        // For case-sensitivity test. (FIXME: if we want HeaderMap to
+        // work in an case-insensitive way (as we do for headers in XHR)
+        // update the test and code)
+        { key: 'content-language',
+          value: 'fi',
+          isNewEntry: true }
+    ];
+
+    var expectedHeaderSize = headers.size;
+    testCasesForSet.forEach(function(testCase) {
+        var key = testCase.key;
+        var value = testCase.value;
+        var expectedValue = ('expectedValue' in testCase) ? testCase.expectedValue : testCase.value;
+        expectedHeaderSize = testCase.isNewEntry ? (expectedHeaderSize + 1) : expectedHeaderSize;
+
+        headers.set(key, value);
+        assert_true(headers.has(key));
+        assert_equals(headers.get(key), expectedValue);
+        if (testCase.isUpdate)
+            assert_true(headers.get(key) != expectedMap[key]);
+        assert_equals(headers.size, expectedHeaderSize);
+
+        // Update expectedMap too for forEach() test below.
+        expectedMap[key] = expectedValue;
+    });
+
+    // 'forEach()'
+    headers.forEach(function(value, key) {
+        assert_true(key != deleteKey);
+        assert_true(key in expectedMap);
+        assert_equals(headers.get(key), expectedMap[key]);
+    });
+
+    // 'forEach()' with thisArg
+    var that = {}, saw_that;
+    headers = new HeaderMap;
+    headers.set('a', 'b');
+    headers.forEach(function() { saw_that = this; }, that);
+    assert_equals(saw_that, that, 'Passed thisArg should match');
+
+    headers.forEach(function() { 'use strict'; saw_that = this; }, 'abc');
+    assert_equals(saw_that, 'abc', 'Passed non-object thisArg should match');
+
+    headers.forEach(function() { saw_that = this; }, null);
+    assert_equals(saw_that, self, 'Passed null thisArg should be replaced with global object');
+
+}, 'HeaderMap in ServiceWorkerGlobalScope');