Add List.insert.

runtime/lib/growable_array.dart

Index: runtime/lib/growable_array.dart
diff --git a/runtime/lib/growable_array.dart b/runtime/lib/growable_array.dart
index e1a858364b035e1c726ecd26c9da234cfeb3f1be..bdfe19cfe88e3f51d1c12419d221bdba3a93d396 100644
--- a/runtime/lib/growable_array.dart
+++ b/runtime/lib/growable_array.dart
@@ -8,6 +8,19 @@ class _GrowableObjectArray<T> implements List<T> {
         "GrowableObjectArray can only be allocated by the VM");
   }
 
+  void insertAt(int index, T element) {
+    if (index is! int) throw new ArgumentError(index);

[srdjan, 2013/03/04 00:53:47]

Per Lars's instructions no explicit type checks should be added. Please remove
line above.

[floitsch, 2013/03/05 17:51:58]

Done.

+    if (index < 0 || index > length) throw new RangeError(index);

[Lasse Reichstein Nielsen, 2013/03/04 09:06:02]

Consider special-casing index == length into 'add'.

[floitsch, 2013/03/05 17:51:58]

Done.

+    int newLength = this.length + 1;
+    this.length = newLength;

[srdjan, 2013/03/04 00:53:47]

Why not just 'this.length+= 1;'?

[Lasse Reichstein Nielsen, 2013/03/04 09:06:02]

Remember oldLength instead. It seems it's what you need below. Or just remember
the number of elements after the index.

[floitsch, 2013/03/05 17:51:58]

Done.

+    Arrays.copy(this,
+                index,
+                this,
+                index + 1,
+                newLength - index - 1);
+    this[index] = element;
+  }
+
   T removeAt(int index) {
     if (index is! int) throw new ArgumentError(index);
     T result = this[index];