Update String.fromCharCodes from sdk

tool/input_sdk/patch/core_patch.dart

Index: tool/input_sdk/patch/core_patch.dart
diff --git a/tool/input_sdk/patch/core_patch.dart b/tool/input_sdk/patch/core_patch.dart
index dc9b72c3e3a68fd2511379cf103fdda64ead3e4d..da771fe5ac93784d8bcfd27193fd893af0e7cb1e 100644
--- a/tool/input_sdk/patch/core_patch.dart
+++ b/tool/input_sdk/patch/core_patch.dart
@@ -17,6 +17,8 @@ import 'dart:_js_helper' show patch,
 
 import 'dart:_foreign_helper' show JS;
 
+import 'dart:_native_typed_data' show NativeUint8List;
+
 String _symbolToString(Symbol symbol) => _symbol_dev.Symbol.getName(symbol);
 
 @patch
@@ -287,26 +289,13 @@ class String {
   @patch
   factory String.fromCharCodes(Iterable<int> charCodes,
                                [int start = 0, int end]) {
-    // If possible, recognize typed lists too.
-    if (charCodes is! JSArray) {
-      return _stringFromIterable(charCodes, start, end);
-    }
-
-    List list = charCodes;
-    int len = list.length;
-    if (start < 0 || start > len) {
-      throw new RangeError.range(start, 0, len);
-    }
-    if (end == null) {
-      end = len;
-    } else if (end < start || end > len) {
-      throw new RangeError.range(end, start, len);
+    if (charCodes is JSArray) {
+      return _stringFromJSArray(charCodes, start, end);
     }
-
-    if (start > 0 || end < len) {
-      list = list.sublist(start, end);
+    if (charCodes is NativeUint8List) {
+      return _stringFromUint8List(charCodes, start, end);
     }
-    return Primitives.stringFromCharCodes(list);
+    return _stringFromIterable(charCodes, start, end);
   }
 
   @patch
@@ -320,6 +309,22 @@ class String {
         'String.fromEnvironment can only be used as a const constructor');
   }
 
+  static String _stringFromJSArray(List list, int start, int endOrNull) {
+    int len = list.length;
+    int end = RangeError.checkValidRange(start, endOrNull, len);
+    if (start > 0 || end < len) {
+      list = list.sublist(start, end);
+    }
+    return Primitives.stringFromCharCodes(list);
+  }
+
+  static String _stringFromUint8List(
+      NativeUint8List charCodes, int start, int endOrNull) {
+    int len = charCodes.length;
+    int end = RangeError.checkValidRange(start, endOrNull, len);
+    return Primitives.stringFromNativeUint8List(charCodes, start, end);
+  }
+
   static String _stringFromIterable(Iterable<int> charCodes,
                                     int start, int end) {
     if (start < 0) throw new RangeError.range(start, 0, charCodes.length);