Service Worker: Fix getRegistrations.html layout test.

LayoutTests/http/tests/serviceworker/getregistrations.html

Index: LayoutTests/http/tests/serviceworker/getregistrations.html
diff --git a/LayoutTests/http/tests/serviceworker/getregistrations.html b/LayoutTests/http/tests/serviceworker/getregistrations.html
index 028ee9c4181f785a461dab903724f159398eed7f..3f6fbaba10767f668317472669ec9226e369e8f4 100644
--- a/LayoutTests/http/tests/serviceworker/getregistrations.html
+++ b/LayoutTests/http/tests/serviceworker/getregistrations.html
@@ -10,27 +10,32 @@
 // getRegistrations() is used in order to avoid adding additional complexity
 // e.g. adding an internal function.
 sequential_promise_test(function(t) {
-    return navigator.serviceWorker.getRegistrations()
-      .then(function(registrations) {
-          return registrations.reduce(function(sequence, registration) {
-              return sequence.then(function() {
-                  return registration.unregister();
-                });
-            }, Promise.resolve());
+    var resolve;
+    var timer;
+    var p = new Promise(function(r) { resolve = r; });
+    navigator.serviceWorker.getRegistrations()
+      .then(function(regs) {
+          return Promise.all(regs.map(function(r) { r.unregister(); }));
+        })
+      .then(function() {
+          // As registration.unregister() promises resolve before the
+          // corresponding registrations are deleted from the storage, we must
+          // wait until the registrations are actually removed from the storage.
+          // Spec reference: https://slightlyoff.github.io/ServiceWorker/spec/service_worker/#unregister-algorithm
+          timer = setInterval(function() {
+              navigator.serviceWorker.getRegistrations()
+                .then(function(regs) {
+                    if (regs.length == 0) {
+                      clearInterval(timer);
+                      resolve();
+                    }
+                  });
+            }, 100);
         });
+    return p;
   }, 'Purge the existing registrations.');
 
 sequential_promise_test(function(t) {
-    return navigator.serviceWorker.getRegistrations()
-      .then(function(value) {
-          assert_array_equals(
-            value,
-            [],
-            'getRegistrations should resolve with an empty array.');
-        });
-  }, 'getRegistrations');
-
-sequential_promise_test(function(t) {
     var scope = 'resources/scope/getregistrations/normal';
     var script = 'resources/empty-worker.js';
     var registrations = [];
@@ -93,8 +98,8 @@ sequential_promise_test(function(t) {
   }, 'Register then Unregister then getRegistrations');
 
 sequential_promise_test(function(t) {
-    // Top-level window's origin is http://127.0.0.1:8000
-    // Set frame's origin to http://localhost:8000
+    // Top-level window's origin: http://127.0.0.1:8000.
+    // Frame's origin: http://localhost:8000.
     var host_info = get_host_info();
     var frame_url = host_info['HTTP_REMOTE_ORIGIN'] +
                     '/serviceworker/resources/frame-for-getregistrations.html';
@@ -105,32 +110,34 @@ sequential_promise_test(function(t) {
 
     return with_iframe(frame_url)
       .then(function(f) {
-          // frame registered its registration scoped
-          // http://localhost:8000/serviceworker/resources/scope-for-getregistrations
           frame = f;
-          // Top-level window registers its registration scoped
-          // http://127.0.0.1:8000/serviceworker/resources/scope-for-getregistrations
-          return service_worker_unregister_and_register(t, script, scope);
-        })
-      .then(function(r) {
-          registrations.push(r);
-          return navigator.serviceWorker.getRegistrations();
-        })
-      .then(function(value) {
-          assert_array_equals(
-            value,
-            registrations,
-            'getRegistrations should only return same origin registrations.');
 
-          var channel = new MessageChannel();
           var resolve;
           var p = new Promise(function(r) { resolve = r; });
 
+          var channel = new MessageChannel();
+
           channel.port1.onmessage = function(e) {
-            if (e.data == 'unregistered')
+            // Frame's registration is registered.
+            if (e.data == 'registered') {
+              // Top-level window registers a registration scoped
+              // http://127.0.0.1:8000/serviceworker/resources/scope-for-getregistrations.
+              service_worker_unregister_and_register(t, script, scope)
+                .then(function(r) {
+                    registrations.push(r);
+                    return navigator.serviceWorker.getRegistrations();
+                  })
+                .then(function(value) {
+                    assert_array_equals(value, registrations,
+                      'getRegistrations should return only the same origin ' +
+                      'registrations.');
+                    channel.port1.postMessage('unregister');
+                  });
+            } else if (e.data == 'unregistered') {
               resolve();
+            }
           };
-          frame.contentWindow.postMessage('unregister', '*', [channel.port2]);
+          frame.contentWindow.postMessage('register', '*', [channel.port2]);
           return p;
         })
       .then(function() {