Add ServiceWorker InstallPhaseEvent.waitUntil() layout test.

LayoutTests/http/tests/serviceworker/resources/install-phase-event-waituntil.js

+pendingPorts = [];
+portResolves = [];
+
+onmessage = function(e) {
+    var message = e.data;
+    if ('port' in message) {
+        var resolve = portResolves.shift();
+        if (resolve)
+            resolve(message.port);
+        else
+            pendingPorts.push(message.port);
+    }
+};
+
+function fulfillPromise() {
+    return new Promise(function(resolve) {
+        // Make sure oninstall/onactivate callback finishes first.
+        setTimeout(function() {
+            var port = pendingPorts.shift();
+            if (port)
+                resolve(port);
+            else
+                portResolves.push(resolve);
+        }, 0);
+    }).then(function(port) {
+        port.postMessage('SYNC');
+        return new Promise(function(resolve) {
+            port.onmessage = function(e) {
+                if (e.data == 'ACK')
+                    resolve();
+            };
+        });
+    });
+}
+
+function rejectPromise() {
+    return new Promise(function(resolve, reject) {
+        setTimeout(reject, 0);
+    });
+}
+
+function stripScopeName(scope) {
+    return scope.split('/').slice(-1)[0];
+}
+
+oninstall = function(e) {
+    var test_switch = stripScopeName(scope);

[falken, 2014/06/30 04:35:31]

could you use "self.scope" to make clear it's a global?

[xiang, 2014/06/30 06:37:11]

OK, I will change that

+    if (test_switch == 'install-fulfilled')
+        e.waitUntil(fulfillPromise());
+    else if (test_switch == 'install-rejected')
+        e.waitUntil(rejectPromise());
+};
+
+onactivate = function(e) {
+    var test_switch = stripScopeName(scope);
+    if (test_switch == 'activate-fulfilled') {
+        e.waitUntil(fulfillPromise());
+    } else if (test_switch == 'activate-rejected') {

[falken, 2014/06/30 04:35:31]

these look like they'd be more readable as a switch statement

[xiang, 2014/06/30 06:37:11]

Yes, will change, thanks.

+        e.waitUntil(rejectPromise());
+    } else if (test_switch == 'activate-multiple-fulfilled') {
+        e.waitUntil(fulfillPromise());
+        e.waitUntil(fulfillPromise());
+    } else if (test_switch == 'activate-reject-precedence') {
+        e.waitUntil(fulfillPromise());
+        e.waitUntil(new Promise(function(resolve, reject) {
+            setTimeout(reject, 0);
+        }));
+    }
+};