Get ride of chrome.storage.* data when removing an application.

chrome/test/data/extensions/platform_apps/reinstall_data_cleanup/test.js

+// Copyright 2013 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.
+
+function testChromeStorage(backend, callback) {
+  backend.get('foo', function(result) {

[not at google - send to devlin, 2014/01/08 18:01:36]

wrap this function(result) in a chrome.test.callbackPass to make sure this never
goes onto the next test, and automatically assert that there was no
chrome.runtime.lastError

+    if (result.foo) {
+      chrome.test.notifyFail('got data before setting!');
+      return;
+    }
+
+    // We set the value but also want to make sure it is correctly saved.
+    backend.set({ 'foo': 'bar' }, function() {
+      backend.get('foo', function(result) {

[not at google - send to devlin, 2014/01/08 18:01:36]

likewise here and the line above. often people alias chrome.test.callbackPass to
"pass".

+        if (result.foo != 'bar')
+          chrome.test.notifyFail('chrome storage unexpected failure');

[not at google - send to devlin, 2014/01/08 18:01:36]

use chrome.test.assertEq('bar', result.foo) for a better failure message and
less code.

the test will exit on failure, so you can just run callback() straight
afterwards:
https://code.google.com/p/chromium/codesearch#chromium/src/chrome/renderer/re...

+        else
+          callback();
+      });
+    });
+  });
+}
+
+function testChromeStorageLocal(callback) {
+  testChromeStorage(chrome.storage.local, callback);

[not at google - send to devlin, 2014/01/08 18:01:36]

callback flow much nicer, and TBH not even sure if these methods are necessary
anymore.

+}
+
+function testChromeStorageSync(callback) {
+  testChromeStorage(chrome.storage.sync, callback);
+}
+
+chrome.app.runtime.onLaunched.addListener(function() {
+  chrome.test.sendMessage('Launched', function() {
+    // Test functions will call a callback if succeeded, notifyFail() otherwise.
+    // The last test function will call notifyPass().
+    testChromeStorageLocal(function() {
+      testChromeStorageSync(function() {
+        chrome.test.notifyPass();
+      });
+    });
+  });
+});