Create IterableMixinWorkaround and move most of the Collections methods there.

tools/dom/templates/immutable_list_mixin.darttemplate

   // -- start List<$E> mixins.
   // $E is the element type.
 
   // From Iterable<$E>:
 
   Iterator<$E> get iterator {
     // Note: NodeLists are not fixed size. And most probably length shouldn't
     // be cached in both iterator _and_ forEach method. For now caching it
     // for consistency.
     return new FixedSizeListIterator<$E>(this);
   }
 
 $if DEFINE_LENGTH_AS_NUM_ITEMS
   // SVG Collections expose numberOfItems rather than length.
   int get length => numberOfItems;
 $endif
   dynamic reduce(dynamic initialValue, dynamic combine(dynamic, $E)) {
-    return Collections.reduce(this, initialValue, combine);
+    return IterableMixinWorkaround.reduce(this, initialValue, combine);
   }
 
 $if DEFINE_CONTAINS
-  bool contains($E element) => Collections.contains(this, element);
+  bool contains($E element) => IterableMixinWorkaround.contains(this, element);
 $else
   // contains() defined by IDL.
 $endif
 
-  void forEach(void f($E element)) => Collections.forEach(this, f);
+  void forEach(void f($E element)) => IterableMixinWorkaround.forEach(this, f);
 
-  String join([String separator]) => Collections.joinList(this, separator);
+  String join([String separator]) => IterableMixinWorkaround.joinList(this, separator);
 
-  List mappedBy(f($E element)) => new MappedList<$E, dynamic>(this, f);
+  List mappedBy(f($E element)) => IterableMixinWorkaround.mappedByList(this, f);
 
-  Iterable<$E> where(bool f($E element)) => new WhereIterable<$E>(this, f);
+  Iterable<$E> where(bool f($E element)) => IterableMixinWorkaround.where(this, f);
 
-  bool every(bool f($E element)) => Collections.every(this, f);
+  bool every(bool f($E element)) => IterableMixinWorkaround.every(this, f);
 
-  bool any(bool f($E element)) => Collections.any(this, f);
+  bool any(bool f($E element)) => IterableMixinWorkaround.any(this, f);
 
   List<$E> toList() => new List<$E>.from(this);
   Set<$E> toSet() => new Set<$E>.from(this);
 
   bool get isEmpty => this.length == 0;
 
-  List<$E> take(int n) => new ListView<$E>(this, 0, n);
+  List<$E> take(int n) => IterableMixinWorkaround.takeList(this, n);
 
   Iterable<$E> takeWhile(bool test($E value)) {
-    return new TakeWhileIterable<$E>(this, test);
+    return IterableMixinWorkaround.takeWhile(this, test);
   }
 
-  List<$E> skip(int n) => new ListView<$E>(this, n, null);
+  List<$E> skip(int n) => IterableMixinWorkaround.skipList(this, n);
 
   Iterable<$E> skipWhile(bool test($E value)) {
-    return new SkipWhileIterable<$E>(this, test);
+    return IterableMixinWorkaround.skipWhile(this, test);
   }
 
   $E firstMatching(bool test($E value), { $E orElse() }) {
-    return Collections.firstMatching(this, test, orElse);
+    return IterableMixinWorkaround.firstMatching(this, test, orElse);
   }
 
   $E lastMatching(bool test($E value), {$E orElse()}) {
-    return Collections.lastMatchingInList(this, test, orElse);
+    return IterableMixinWorkaround.lastMatchingInList(this, test, orElse);
   }
 
   $E singleMatching(bool test($E value)) {
-    return Collections.singleMatching(this, test);
+    return IterableMixinWorkaround.singleMatching(this, test);
   }
 
   $E elementAt(int index) {
     return this[index];
   }
 
   // From Collection<$E>:
 
   void add($E value) {
     throw new UnsupportedError("Cannot add to immutable List.");
@@ skipping 43 matching lines @@
     if (this.length > 0) return this[this.length - 1];
     throw new StateError("No elements");
   }
 
   $E get single {
     if (length == 1) return this[0];
     if (length == 0) throw new StateError("No elements");
     throw new StateError("More than one element");
   }
 
-  $E min([int compare($E a, $E b)]) => Collections.min(this, compare);
+  $E min([int compare($E a, $E b)]) => IterableMixinWorkaround.min(this, compare);
 
-  $E max([int compare($E a, $E b)]) => Collections.max(this, compare);
+  $E max([int compare($E a, $E b)]) => IterableMixinWorkaround.max(this, compare);
 
   $E removeAt(int pos) {
     throw new UnsupportedError("Cannot removeAt on immutable List.");
   }
 
   $E removeLast() {
     throw new UnsupportedError("Cannot removeLast on immutable List.");
   }
 
   void setRange(int start, int rangeLength, List<$E> from, [int startFrom]) {
     throw new UnsupportedError("Cannot setRange on immutable List.");
   }
 
   void removeRange(int start, int rangeLength) {
     throw new UnsupportedError("Cannot removeRange on immutable List.");
   }
 
   void insertRange(int start, int rangeLength, [$E initialValue]) {
     throw new UnsupportedError("Cannot insertRange on immutable List.");
   }
 
   List<$E> getRange(int start, int rangeLength) =>
       Lists.getRange(this, start, rangeLength, <$E>[]);
 
   // -- end List<$E> mixins.