Fix more lint style issues in runtime patches.

runtime/lib/timer_impl.dart

 // Copyright (c) 2013, 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.
 
+import 'dart:_internal' hide Symbol;
+
 // Timer heap implemented as a array-based binary heap[0].
 // This allows for O(1) `first`, O(log(n)) `remove`/`removeFirst` and O(log(n))
 // `add`.
 //
 // To ensure the timers are ordered by insertion time, the _Timer class has a
 // `_id` field set when added to the heap.
 //
 // [0] http://en.wikipedia.org/wiki/Binary_heap
 class _TimerHeap {
   List<_Timer> _list;
@@ skipping 448 matching lines @@
       return new _Timer.periodic(milliSeconds, callback);
     }
     return new _Timer(milliSeconds, callback);
   }
 }
 
 
 _setupHooks() {
   VMLibraryHooks.timerFactory = _Timer._factory;
 }