Add a simple fetch API test.

LayoutTests/http/tests/fetch/script-tests/simple.js

+var global = this;
+if (global.importScripts) {
+  importScripts('/resources/testharness.js');
+}
+
+promise_test(function(test) {
+    return Promise.resolve().then(function() {
+        return fetch(new Request('/fetch/resources/hello.txt'));
+    }).then(function(res) {

[hiroshige, 2014/12/19 07:41:20]

Indent +2 spaces.

[yhirano, 2014/12/19 09:29:08]

Done.

+        return res.text();
+    }).then(function(text) {

[hiroshige, 2014/12/19 07:41:20]

Indent +2 spaces.

[yhirano, 2014/12/19 09:29:08]

Done.

+        assert_equals(text, 'hello, world\n');

[hiroshige, 2014/12/19 07:41:20]

Add an assert message such as "Response text should be the same with the content
of hello.txt".

[yhirano, 2014/12/19 09:29:08]

Done.

+    });

[hiroshige, 2014/12/19 07:41:20]

Indent +2 spaces.

[yhirano, 2014/12/19 09:29:08]

Done.

+});

[hiroshige, 2014/12/19 07:41:20]

Indent +2 spaces.

[yhirano, 2014/12/19 09:29:08]

Done.

+
+done();