Add methods to Collection.

sdk/lib/core/collection.dart

Index: sdk/lib/core/collection.dart
diff --git a/sdk/lib/core/collection.dart b/sdk/lib/core/collection.dart
index 23b08e6b4b008e89eb954a2ff696923b0fdb1f34..48ab1de2e88cd30f0c8d0e212d2077d6c472a622 100644
--- a/sdk/lib/core/collection.dart
+++ b/sdk/lib/core/collection.dart
@@ -5,11 +5,83 @@
 part of dart.core;
 
 /**
- * The common interface of all collections.
+ * A collection of individual elements.
  *
- * The [Collection] class contains a skeleton implementation of
- * an iterator based collection.
+ * A [Collection] contains some elements in a structure optimized
+ * for certain operations. Different collections are optimized for different
+ * uses.
+ *
+ * A collection can be updated by adding or removing elements.
+ *
+ * Collections are [Iterable]. The order of iteration is defined by
+ * each type of collection.
  */
 abstract class Collection<E> extends Iterable<E> {
   const Collection();
+
+  /**
+   * Adds an element to this collection.
+   */
+  void add(E element);
+
+  /**
+   * Adds all of [elements] to this collection.
+   *
+   * Equivalent to adding each element in [elements] using [add],
+   * but some collections may be able to optimize it.
+   */
+  void addAll(Iterable<E> elements) {
+    for (E element in elements) {
+      add(element);
+    }
+  }
+
+  /**
+   * Removes an instance of [element] from this collection.
+   *
+   * This removes only one instance of the element for collections that can
+   * contain the same element more than once (e.g., [List]). Which instance
+   * is removed is decided by the collection.
+   *
+   * Has no effect if the elements is not in this collection.
+   */
+  void remove(Object element);
+
+  /**
+   * Removes all of [elements] from this collection.
+   *
+   * Equivalent to calling [remove] once for each element in
+   * [elements], but may be faster for some collections.
+   */
+  void removeAll(Iterable elements) {
+    IterableMixinWorkaround.removeAll(this, elements);
+  }
+
+  /**
+   * Removes all elements of this collection that are not
+   * in [elements].
+   *
+   * For [Set]s, this is the intersection of the two original sets.
+   */
+  void retainAll(Iterable elements) {
+    IterableMixinWorkaround.retainAll(this, elements);
+  }
+
+  /**
+   * Removes all elements of this collection that satisfy [test].
+   *
+   * An elements [:e:] satisfies [test] if [:test(e):] is true.
+   */
+  void removeMatching(bool test(E element)) {
+    IterableMixinWorkaround.removeMatching(this, test);
+  }
+
+  /**
+   * Removes all elements of this collection that fail to satisfy [test].
+   *
+   * An elements [:e:] satisfies [test] if [:test(e):] is true.
+   */
+  void retainMatching(bool test(E element)) {
+    IterableMixinWorkaround.retainMatching(this, test);
+  }
 }