Add a new app API to enable watchdog behavior restarts in kiosk apps

chrome/test/data/extensions/api_test/runtime/restartOnWatchdog/test.js

+// 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.
+
+var sendMessage = chrome.test.sendMessage;
+
+function assertTrue(condition) {
+  chrome.test.assertTrue(condition);
+  if (!condition)
+    sendMessage('fail');
+}
+
+function testRestartOnWatchdog() {
+  sendMessage('ready', function(response) {
+    if (response == 'test1') {
+      chrome.runtime.restartOnWatchdog(-1, function() {
+        // Even though there's nothing schduled right now, this call should
+        // succeed.
+        assertTrue(chrome.runtime.lastError === undefined);

[Devlin, 2016/05/25 21:53:21]

nit: prefer "assertNoLastError()"

[afakhry, 2016/05/26 00:18:39]

Done.

+        testRestartOnWatchdog();
+      });
+    } else if (response == 'test2') {
+      chrome.runtime.restartOnWatchdog(2, function() {
+        // This request will be successfully rescheduled even though it will

[Devlin, 2016/05/25 21:53:21]

rescheduled?  When was it first scheduled?

[afakhry, 2016/05/26 00:18:39]

Done.

+        // be cancelled by test3.
+        assertTrue(chrome.runtime.lastError === undefined);
+        sendMessage('request1', function(response) {

[Devlin, 2016/05/25 21:53:21]

nit: might be a bit easier to read these if the numbers matched the test number
- maybe something like "responseN"?

[afakhry, 2016/05/26 00:18:39]

Done.

+          testRestartOnWatchdog();
+        });
+      });
+    } else if (response == 'test3') {
+      chrome.runtime.restartOnWatchdog(2, function() {
+        assertTrue(chrome.runtime.lastError === undefined);
+        sendMessage('request2', function(response) {
+          testRestartOnWatchdog();
+        });
+      });
+    } else if (response == 'test4') {
+      // This cancels any previous restart request.
+      chrome.runtime.restartOnWatchdog(-1, function() {
+        assertTrue(chrome.runtime.lastError === undefined);
+        sendMessage('request3', function(response) {
+          testRestartOnWatchdog();
+        });
+      });
+    } else if (response == 'test5') {
+      // The test will wait for this request until the restart request is
+      // successfully accomplished.
+      chrome.runtime.restartOnWatchdog(3, function() {
+        assertTrue(chrome.runtime.lastError === undefined);
+        sendMessage('request4', function(response) {
+          testRestartOnWatchdog();
+        });
+      });
+    } else if (response = 'test6') {
+      // Too soon request after a successful restart. It will be throttled and
+      // scheduled to happen after 3 seconds, even though we requested 1 second.

[Devlin, 2016/05/25 21:53:21]

API question - should we automatically reschedule for the minimum time, or just
throw an error saying "too soon after last restart"?

[afakhry, 2016/05/26 00:18:39]

Me and Xiyuan agreed to schedule a restart after the minimum time has passed. 

+      chrome.runtime.restartOnWatchdog(1, function() {
+        assertTrue(chrome.runtime.lastError === undefined);
+        sendMessage('request5', function(response) {
+          testRestartOnWatchdog();
+        });
+      });
+    } else if (response == 'success') {

[Devlin, 2016/05/25 21:53:21]

needed?

[afakhry, 2016/05/26 00:18:39]

No, I was just being explicit. Removed.

+      return;
+    }
+  });
+}
+
+testRestartOnWatchdog();