Make List.remove return boolean.

sdk/lib/collection/list.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.
 
 part of dart.collection;
 
 /**
  * Abstract implementation of a list.
  *
  * All operations are defined in terms of `length`, `operator[]`,
@@ skipping 224 matching lines @@
   void add(E element) {
     this[this.length++] = element;
   }
 
   void addAll(Iterable<E> iterable) {
     for (E element in iterable) {
       this[this.length++] = element;
     }
   }
 
-  void remove(Object element) {
+  bool remove(Object element) {
     for (int i = 0; i < this.length; i++) {
       if (this[i] == element) {
-        this.setRange(i, i + this.length - 1, this, i + 1);
+        this.setRange(i, this.length - 1, this, i + 1);
         this.length -= 1;
-        return;
+        return true;
       }
     }
+    return false;
   }
 
   void removeWhere(bool test(E element)) {
     _filter(this, test, false);
   }
 
   void retainWhere(bool test(E element)) {
     _filter(this, test, true);
   }
 
@@ skipping 24 matching lines @@
   E removeLast() {
     if (length == 0) {
       throw new StateError("No elements");
     }
     E result = this[length - 1];
     length--;
     return result;
   }
 
   void sort([Comparator<E> compare]) {
+    if (compare == null) compare = Comparable.compare;
     Sort.sort(this, compare);
   }
 
   Map<int, E> asMap() {
     return new ListMapView(this);
   }
 
   void _rangeCheck(int start, int end) {
     if (start < 0 || start > this.length) {
       throw new RangeError.range(start, 0, this.length);
@@ skipping 158 matching lines @@
       for (E element in iterable) {
         this[index++] = element;
       }
     }
   }
 
   Iterable<E> get reversed => new ReversedListIterable(this);
 
   String toString() => ToString.iterableToString(this);
 }