Move StringImplementation from coreimpl to core as _StringImpl.

lib/compiler/implementation/lib/coreimpl_patch.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.
 
 // Patch file for dart:coreimpl classes.
 
-// Patch for String implementation.
-// TODO(ager): Split out into date_patch.dart and allow #source
-// in patch files?
-patch class StringImplementation {
-  patch static String _fromCharCodes(List<int> charCodes) {
-    checkNull(charCodes);
-    if (!isJsArray(charCodes)) {
-      if (charCodes is !List) throw new ArgumentError(charCodes);
-      charCodes = new List.from(charCodes);
-    }
-    return Primitives.stringFromCharCodes(charCodes);
-  }
-
-  patch String join(List<String> strings, String separator) {
-    checkNull(strings);
-    checkNull(separator);
-    if (separator is !String) throw new ArgumentError(separator);
-    return stringJoinUnchecked(_toJsStringArray(strings), separator);
-  }
-
-  patch String concatAll(List<String> strings) {
-    return stringJoinUnchecked(_toJsStringArray(strings), "");
-  }
-
-  static List _toJsStringArray(List<String> strings) {
-    checkNull(strings);
-    var array;
-    final length = strings.length;
-    if (isJsArray(strings)) {
-      array = strings;
-      for (int i = 0; i < length; i++) {
-        final string = strings[i];
-        checkNull(string);
-        if (string is !String) throw new ArgumentError(string);
-      }
-    } else {
-      array = new List(length);
-      for (int i = 0; i < length; i++) {
-        final string = strings[i];
-        checkNull(string);
-        if (string is !String) throw new ArgumentError(string);
-        array[i] = string;
-      }
-    }
-    return array;
-  }
-}
-
-
 // Patch for RegExp implementation.
 // TODO(ager): Split out into regexp_patch.dart and allow #source in
 // patch files?
 patch class JSSyntaxRegExp {
   final String _pattern;
   final bool _multiLine;
   final bool _ignoreCase;
 
   patch const JSSyntaxRegExp(String pattern,
                              {bool multiLine: false,
@@ skipping 105 matching lines @@
     // hidden global flag.
     _next = _re.firstMatch(_str);
     if (_next == null) {
       _done = true;
       return false;
     } else {
       return true;
     }
   }
 }