Refactor List.setRange function.

runtime/lib/array.dart

Index: runtime/lib/array.dart
diff --git a/runtime/lib/array.dart b/runtime/lib/array.dart
index 2478686b5aa44cdc324ffb97ca7b9119b801f570..fe18eab4abf674b149533e3ace08aefc34844dee 100644
--- a/runtime/lib/array.dart
+++ b/runtime/lib/array.dart
@@ -65,10 +65,14 @@ class _ObjectArray<E> implements List<E> {
   }
 
   // List interface.
-  void setRange(int start, int length, List<E> from, [int startFrom = 0]) {
-    if (length < 0) {
-      throw new ArgumentError("negative length $length");
+  void setRange(int start, int end, List<E> from, [int startFrom = 0]) {
+    if (start < 0 || start > this.length) {
+      throw new RangeError.range(start, 0, this.length);
     }
+    if (end < 0 || end > this.length) {
+      throw new RangeError.range(end, start, this.length);
+    }
+    int length = end - start;
     if (from is _ObjectArray) {
       _copyFromObjectArray(from, startFrom, start, length);
     } else {
@@ -317,7 +321,7 @@ class _ImmutableArray<E> implements List<E> {
         "Cannot modify an immutable array");
   }
 
-  void setRange(int start, int length, List<E> from, [int startFrom = 0]) {
+  void setRange(int start, int end, List<E> from, [int startFrom = 0]) {
     throw new UnsupportedError(
         "Cannot modify an immutable array");
   }