Fix indexed_db strong mode warnings.

tools/dom/templates/html/impl/impl_IDBFactory.darttemplate

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of $LIBRARYNAME;
 
 $(ANNOTATIONS)$(NATIVESPEC)$(CLASS_MODIFIERS)class $CLASSNAME$EXTENDS$IMPLEMENTS {
   /**
    * Checks to see if Indexed DB is supported on the current platform.
    */
@@ skipping 31 matching lines @@
         request.onBlocked.listen(onBlocked);
       }
       return _completeRequest(request);
     } catch (e, stacktrace) {
       return new Future.error(e, stacktrace);
     }
   }
 
   @DomName('IDBFactory.deleteDatabase')
   Future<IdbFactory> deleteDatabase(String name,
-      {void onBlocked(Event)}) {
+      {void onBlocked(Event e)}) {
     try {
       var request = _deleteDatabase(name);
 
       if (onBlocked != null) {
         request.onBlocked.listen(onBlocked);
       }
-      var completer = new Completer.sync();
+      var completer = new Completer<IdbFactory>.sync();
       request.onSuccess.listen((e) {
         completer.complete(this);
       });
       request.onError.listen(completer.completeError);
       return completer.future;
     } catch (e, stacktrace) {
       return new Future.error(e, stacktrace);
     }
   }
 
@@ skipping 23 matching lines @@
   }
 
 $!MEMBERS
 }
 
 
 /**
  * Ties a request to a completer, so the completer is completed when it succeeds
  * and errors out when the request errors.
  */
-Future _completeRequest(Request request) {
-  var completer = new Completer.sync();
+Future/*<T>*/ _completeRequest/*<T>*/(Request request) {
+  var completer = new Completer/*<T>*/.sync();
   // TODO: make sure that completer.complete is synchronous as transactions
   // may be committed if the result is not processed immediately.
   request.onSuccess.listen((e) {
-    completer.complete(request.result);
+    completer.complete(request.result as dynamic/*=T*/);
   });
   request.onError.listen(completer.completeError);
   return completer.future;
 }