Change List constructors.

runtime/lib/string_base.dart

Index: runtime/lib/string_base.dart
diff --git a/runtime/lib/string_base.dart b/runtime/lib/string_base.dart
index 11b594ed9e562cebc71e654acdb8b433678031f5..55c60bb1fb7edbe003452ef9f480e8e2de9dab7d 100644
--- a/runtime/lib/string_base.dart
+++ b/runtime/lib/string_base.dart
@@ -232,7 +232,7 @@ class _StringBase {
    */
   static String _interpolate(List values) {
     int numValues = values.length;
-    var stringList = new List(numValues);
+    var stringList = new List.fixedLength(numValues);
     for (int i = 0; i < numValues; i++) {
       stringList[i] = values[i].toString();
     }
@@ -295,7 +295,7 @@ class _StringBase {
 
   List<String> splitChars() {
     int len = this.length;
-    final result = new List<String>(len);
+    final result = new List<String>.fixedLength(len);
     for (int i = 0; i < len; i++) {
       result[i] = this[i];
     }
@@ -304,7 +304,7 @@ class _StringBase {
 
   List<int> get charCodes {
     int len = this.length;
-    final result = new List<int>(len);
+    final result = new List<int>.fixedLength(len);
     for (int i = 0; i < len; i++) {
       result[i] = this.charCodeAt(i);
     }
@@ -324,7 +324,7 @@ class _StringBase {
 
     List stringsList = strings;
     if (separator.length != 0) {
-      stringsList = new List(2 * length - 1);
+      stringsList = new List.fixedLength(2 * length - 1);
       stringsList[0] = strings[0];
       int j = 1;
       for (int i = 1; i < length; i++) {