Unify String.

corelib/src/strings.dart

Index: corelib/src/strings.dart
diff --git a/corelib/src/strings.dart b/corelib/src/strings.dart
index 9462ee10eb9fc7a76f7e98f8c04f0b095f4bab52..a3adffd299aa93fd11665c7a7cadb492737b8c06 100644
--- a/corelib/src/strings.dart
+++ b/corelib/src/strings.dart
@@ -3,26 +3,17 @@
 // BSD-style license that can be found in the LICENSE file.
 
 class Strings {
-
-  /**
-   * Factory implementation of String.fromCharCodes:
-   * Allocates a new String for the specified [charCodes].
-   */
-  factory String.fromCharCodes(List<int> charCodes) {
-    return StringBase.createFromCharCodes(charCodes);
-  }
-
   /**
    * Joins all the given strings to create a new string.
    */
   static String join(List<String> strings, String separator) {
-    return StringBase.join(strings, separator);
+    return StringImplementation.join(strings, separator);
   }
 
   /**
    * Concatenates all the given strings to create a new string.
    */
   static String concatAll(List<String> strings) {
-    return StringBase.concatAll(strings);
+    return StringImplementation.concatAll(strings);
   }
 }