Inline native String.charCodeAt in optimized code.

tests/language/optimized_string_charcodeat.dart

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Test optimized charCodeAt and array access.
+
+String one_byte = "hest";
+String two_byte = "høns";
+
+int testOneByteCharCodeAt(String x, int i) {
+  int test() {
+    return x.charCodeAt(i);
+  }
+  for (int i = 0; i < 10000; i++) test();
+  return test();
+}
+
+
+int testTwoByteCharCodeAt(String x, int i) {
+  int test() {
+    return x.charCodeAt(i);
+  }
+  for (int i = 0; i < 10000; i++) test();
+  return test();
+}
+
+
+int testConstantStringCharCodeAt(int i) {
+  int test() {
+    return "høns".charCodeAt(i);
+  }
+  for (int i = 0; i < 10000; i++) test();
+  return test();
+}
+
+
+int testConstantIndexCharCodeAt(String x) {
+  int test() {
+    return x.charCodeAt(1);
+  }
+  for (int i = 0; i < 10000; i++) test();
+  return test();
+}
+
+
+main() {
+  Expect.equals(101, testOneByteCharCodeAt(one_byte, 1));
+  Expect.equals(248, testTwoByteCharCodeAt(two_byte, 1));
+  Expect.equals(248, testConstantStringCharCodeAt(1));
+  Expect.equals(101, testConstantIndexCharCodeAt(one_byte));
+}