Added browser tests to test the BudgetAPI. Also added BudgetAPI to ExperimentalWebPlatformFeatures.

chrome/test/data/budget_service/budget_test.js

Index: chrome/test/data/budget_service/budget_test.js
diff --git a/chrome/test/data/budget_service/budget_test.js b/chrome/test/data/budget_service/budget_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..21a189dae9171e42968be8e265d7e3efb9a2e90c
--- /dev/null
+++ b/chrome/test/data/budget_service/budget_test.js
@@ -0,0 +1,109 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+'use strict';
+
+var resultQueue = new ResultQueue();
+
+// Sends data back to the test. This must be in response to an earlier
+// request, but it's ok to respond asynchronously. The request blocks until
+// the response is sent.
+function sendResultToTest(result) {
+  console.log('sendResultToTest: ' + result);
+  if (window.domAutomationController) {
+    domAutomationController.send('' + result);
+  }
+}
+
+function sendErrorToTest(error) {
+  sendResultToTest(error.name + ' - ' + error.message);
+}
+
+// Queue storing asynchronous results received from the Service Worker. Results
+// are sent to the test when requested.
+function ResultQueue() {

[Peter Beverloo, 2016/09/27 15:57:47]

Could we share this code with the push messaging test by just including it
through a <script> tag?

[harkness, 2016/09/28 12:29:21]

Done.

+  // Invariant: this.queue.length == 0 || this.pendingGets == 0
+  this.queue = [];
+  this.pendingGets = 0;
+}
+
+// Adds a data item to the queue. Will be sent to the test if there are
+// pendingGets.
+ResultQueue.prototype.push = function(data) {
+  if (this.pendingGets > 0) {
+    this.pendingGets--;
+    sendResultToTest(data);
+  } else {
+    this.queue.unshift(data);
+  }
+};
+
+// Called by native. Sends the next data item to the test if it is available.
+// Otherwise increments pendingGets so it will be delivered when received.
+ResultQueue.prototype.pop = function() {
+  if (this.queue.length) {
+    sendResultToTest(this.queue.pop());
+  } else {
+    this.pendingGets++;
+  }
+};
+
+// Called by native. Immediately sends the next data item to the test if it is
+// available, otherwise sends null.
+ResultQueue.prototype.popImmediately = function() {
+  sendResultToTest(this.queue.length ? this.queue.pop() : null);
+};
+
+function registerServiceWorker() {
+  // The base dir used to resolve service_worker.js.
+  navigator.serviceWorker.register('service_worker.js', {scope: './'}).then(
+      function(swRegistration) {
+        sendResultToTest('ok - service worker registered');
+      }, sendErrorToTest);
+}
+
+// Query for the budget and return the current total.
+function documentGetBudget() {
+  navigator.budget.getBudget().then(function(budget) {
+    sendResultToTest("ok - budget returned value of " + budget[0].budgetAt);
+  }, function() {
+    sendResultToTest("failed - unable to get budget values");
+  });
+}
+
+// Request a reservation for a silent push.
+function documentReserveBudget() {
+  navigator.budget.reserve('silent-push').then(function(reserved) {
+    if (reserved)
+      sendResultToTest("ok - reserved budget");
+    else
+      sendResultToTest("failed - not able to reserve budget");
+  }, function() {
+    sendResultToTest("failed - error while trying to reserve budget");
+  });
+}
+
+function workerGetBudget() {
+  navigator.serviceWorker.controller.postMessage({command: 'workerGet'});
+}
+
+function workerReserveBudget() {
+  navigator.serviceWorker.controller.postMessage({command: 'workerReserve'});
+}
+
+function isControlled() {
+  if (navigator.serviceWorker.controller) {
+    sendResultToTest('true - is controlled');
+  } else {
+    sendResultToTest('false - is not controlled');
+  }
+}
+
+navigator.serviceWorker.addEventListener('message', function(event) {
+  var message = JSON.parse(event.data);
+  if (message.type == 'push')
+    resultQueue.push(message.data);
+  else
+    sendResultToTest(message.data);
+}, false);