- Fix for issue 27054 (leak when removing element from _GrowableList)

runtime/lib/growable_array.dart

 // 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.
 
 class _GrowableList<T> extends ListBase<T> {
 
   void insert(int index, T element) {
     if ((index < 0) || (index > length)) {
       throw new RangeError.range(index, 0, length);
     }
@@ skipping 94 matching lines @@
   }
 
   factory _GrowableList.withData(_List data)
     native "GrowableList_allocate";
 
   int get _capacity native "GrowableList_getCapacity";
 
   int get length native "GrowableList_getLength";
 
   void set length(int new_length) {
-    int new_capacity = (new_length == 0) ? _kDefaultCapacity : new_length;
-    if (new_capacity > _capacity) {
+    int old_capacity = _capacity;
+    int new_capacity = new_length;
+    if (new_length == 0) {
+      // Ensure that we use _kDefaultCapacity only when the old_capacity
+      // is greater than _kDefaultCapacity otherwise we end up growing the
+      // the array.
+      if (old_capacity < _kDefaultCapacity) {
+        new_capacity = old_capacity;
+      } else {
+        new_capacity = _kDefaultCapacity;
+      }
+    }
+    if (new_capacity > old_capacity) {
       _grow(new_capacity);
       _setLength(new_length);
       return;
     }
     // We are shrinking. Pick the method which has fewer writes.
     // In the shrink-to-fit path, we write |new_capacity + new_length| words
     // (null init + copy).
     // In the non-shrink-to-fit path, we write |length - new_length| words
     // (null overwrite).
     final bool shouldShrinkToFit =
@@ skipping 69 matching lines @@
         if (this.length != newLen) throw new ConcurrentModificationError(this);
         len = newLen;
       }
       _grow(_capacity * 2);
     } while (true);
   }
 
   T removeLast() {
     var len = length - 1;
     var elem = this[len];
-    this[len] = null;
-    _setLength(len);
+    this.length = len;
     return elem;
   }
 
   T get first {
     if (length > 0) return this[0];
     throw IterableElementError.noElement();
   }
 
   T get last {
     if (length > 0) return this[length - 1];
@@ skipping 132 matching lines @@
       result._setLength(length);
       return result;
     }
     return growable ? <T>[] : new List<T>(0);
   }
 
   Set<T> toSet() {
     return new Set<T>.from(this);
   }
 }