Remove Collection, Collections and clean up List/Set/Queue implementations of retain/remove.

sdk/lib/html/html_common/filtered_element_list.dart

Index: sdk/lib/html/html_common/filtered_element_list.dart
diff --git a/sdk/lib/html/html_common/filtered_element_list.dart b/sdk/lib/html/html_common/filtered_element_list.dart
index 88a5767d5809dd513f96b69997d0df0b013c8b4f..bb253e68ed1a6d4aa976906a8a888df4a902dcf8 100644
--- a/sdk/lib/html/html_common/filtered_element_list.dart
+++ b/sdk/lib/html/html_common/filtered_element_list.dart
@@ -122,24 +122,6 @@ class FilteredElementList extends ListBase<Element> {
     }
   }
 
-  // Operations defined in terms of [Collections]' [remove].
-
-  void removeAll(Iterable elements) {
-    // This should be optimized to not use [remove] directly.
-    IterableMixinWorkaround.removeAll(this, elements);
-  }
-
-  void retainAll(Iterable elements) {
-    IterableMixinWorkaround.retainAll(this, elements);
-  }
-
-  void removeWhere(bool test(Element element)) {
-    IterableMixinWorkaround.removeWhere(this, test);
-  }
-
-  void retainWhere(bool test(Element element)) {
-    IterableMixinWorkaround.retainWhere(this, test);
-  }
 
   Element reduce(Element combine(Element value, Element element)) {
     return _filtered.reduce(combine);