[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');