Dartifying some IndexedDB APIs.

tests/html/indexeddb_2_test.dart

 library IndexedDB1Test;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
+import 'dart:async';
 import 'dart:html' as html;
 import 'dart:indexed_db' as idb;
 import 'dart:collection';
 import 'utils.dart';
 
 // Write and re-read Maps: simple Maps; Maps with DAGs; Maps with cycles.
 
 const String DB_NAME = 'Test';
 const String STORE_NAME = 'TEST';
 const int VERSION = 1;
 
 testReadWrite(key, value, check,
-              [dbName = DB_NAME,
-               storeName = STORE_NAME,
-               version = VERSION]) => () {
-  var db;
+              [dbName = DB_NAME, storeName = STORE_NAME, version = VERSION]) {
 
-  fail(e) {
-    guardAsync(() {
-      throw new Exception('IndexedDB failure');
-    });
-  }
-
-  createObjectStore(db) {
-    var store = db.createObjectStore(storeName);
+  createObjectStore(e) {
+    var store = e.target.result.createObjectStore(storeName);
     expect(store, isNotNull);
   }
 
-  step2(e) {
-    var transaction = db.transaction(storeName, 'readonly');
-    var request = transaction.objectStore(storeName).getObject(key);
-    request.onSuccess.listen(expectAsync1((e) {
-      var object = e.target.result;
+  var db;
+  return chainSteps([
+    () {
+      // Delete any existing DBs.
+      return html.window.indexedDB.deleteDatabase(dbName);
+    },
+    (_) {
+      return html.window.indexedDB.open(dbName, version: version,
+        onUpgradeNeeded: createObjectStore);
+    },
+    (result) {
+      db = result;
+      var transaction = db.transaction([storeName], 'readwrite');
+      return transaction.objectStore(storeName).put(value, key);
+    },
+    (key) {
+      var transaction = db.transaction(storeName, 'readonly');
+      return transaction.objectStore(storeName).getObject(key);
+    },
+    (object) {
       db.close();
       check(value, object);
-    }));
-    request.onError.listen(fail);
-  }
-
-  step1() {
-    var transaction = db.transaction([storeName], 'readwrite');
-    var request = transaction.objectStore(storeName).put(value, key);
-    request.onSuccess.listen(expectAsync1(step2));
-    request.onError.listen(fail);
-  }
-
-  initDb(e) {
-    db = e.target.result;
-    if (version != db.version) {
-      // Legacy 'setVersion' upgrade protocol.
-      var request = db.setVersion('$version');
-      request.onSuccess.listen(
-        expectAsync1((e) {
-          createObjectStore(db);
-          var transaction = e.target.result;
-          transaction.onComplete.listen(expectAsync1((e) => step1()));
-          transaction.onError.listen(fail);
-        })
-      );
-      request.onError.listen(fail);
-    } else {
-      step1();
     }
-  }
-
-  openDb(e) {
-    var request = html.window.indexedDB.open(dbName, version);
-    expect(request, isNotNull);
-    request.onSuccess.listen(expectAsync1(initDb));
-    request.onError.listen(fail);
-    if (request is idb.OpenDBRequest) {
-      // New upgrade protocol.  Old API has no 'upgradeNeeded' and uses
-      // setVersion instead.
-      request.onUpgradeNeeded.listen((e) {
-          guardAsync(() {
-              createObjectStore(e.target.result);
-            });
-        });
-    }
-  }
-
-  // Delete any existing DB.
-  var deleteRequest = html.window.indexedDB.deleteDatabase(dbName);
-  deleteRequest.onSuccess.listen(expectAsync1(openDb));
-  deleteRequest.onError.listen(fail);
-};
+  ]);
+}
 
 
 main() {
   useHtmlConfiguration();
 
   var obj1 = {'a': 100, 'b': 's'};
   var obj2 = {'x': obj1, 'y': obj1};  // DAG.
 
   var obj3 = {};
   obj3['a'] = 100;
   obj3['b'] = obj3;  // Cycle.
 
   var obj4 = new SplayTreeMap<String, dynamic>();  // Different implementation.
   obj4['a'] = 100;
   obj4['b'] = 's';
 
   var cyclic_list = [1, 2, 3];
   cyclic_list[1] = cyclic_list;
 
-  go(name, data) => test(name, testReadWrite(123, data, verifyGraph));
+  go(name, data) => futureTest(name,
+    () => testReadWrite(123, data, verifyGraph));
 
   test('test_verifyGraph', () {
       // Nice to know verifyGraph is working before we rely on it.
       verifyGraph(obj4, obj4);
       verifyGraph(obj1, new Map.from(obj1));
       verifyGraph(obj4, new Map.from(obj4));
 
       var l1 = [1,2,3];
       var l2 = [const [1, 2, 3], const [1, 2, 3]];
       verifyGraph([l1, l1], l2);
       expect(() => verifyGraph([[1, 2, 3], [1, 2, 3]], l2), throws);
 
       verifyGraph(cyclic_list, cyclic_list);
     });
 
   // Don't bother with these tests if it's unsupported.
   // Support is tested in indexeddb_1_test
   if (idb.IdbFactory.supported) {
     go('test_simple', obj1);
     go('test_DAG', obj2);
     go('test_cycle', obj3);
     go('test_simple_splay', obj4);
     go('const_array_1', const [const [1], const [2]]);
     go('const_array_dag', const [const [1], const [1]]);
     go('array_deferred_copy', [1,2,3, obj3, obj3, 6]);
     go('array_deferred_copy_2', [1,2,3, [4, 5, obj3], [obj3, 6]]);
     go('cyclic_list', cyclic_list);
   }
 }