fileSystemProvider: First cut at implementing fileSystemProvider API

chrome/test/data/extensions/api_test/file_system_provider/mount/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.
+
+chrome.test.runTests([
+  function goodDisplayName() {
+    chrome.fileSystemProvider.mount(
+      'test file system',
+      function(error, fileSystemId) {
+        chrome.test.assertEq('OK', error.name);
+        chrome.test.assertTrue(fileSystemId != '');
+        chrome.test.succeed();
+      }
+    );
+  },
+  function emptyDisplayName() {
+    chrome.fileSystemProvider.mount(
+      '',
+      function(error, fileSystemId) {
+        chrome.test.assertEq('SecurityError', error.name);
+        chrome.test.succeed();
+      }
+    );
+  },
+]);