Remove insertRange.

sdk/lib/_collection_dev/list.dart

Index: sdk/lib/_collection_dev/list.dart
diff --git a/sdk/lib/_collection_dev/list.dart b/sdk/lib/_collection_dev/list.dart
index 11811dfaa186c3fef9f34af214b9b0585f50b7cf..3deb4050772b2968608f25dcb7fff25032c93a0b 100644
--- a/sdk/lib/_collection_dev/list.dart
+++ b/sdk/lib/_collection_dev/list.dart
@@ -74,11 +74,6 @@ abstract class FixedLengthListMixin<E>  {
     throw new UnsupportedError(
         "Cannot remove from a fixed-length list");
   }
-
-  void insertRange(int start, int length, [E initialValue]) {
-    throw new UnsupportedError(
-        "Cannot insert range in a fixed-length list");
-  }
 }
 
 /**
@@ -169,11 +164,6 @@ abstract class UnmodifiableListMixin<E> {
     throw new UnsupportedError(
         "Cannot remove from an unmodifiable list");
   }
-
-  void insertRange(int start, int length, [E initialValue]) {
-    throw new UnsupportedError(
-        "Cannot insert range in an unmodifiable list");
-  }
 }
 
 /**