Remove deprecated string features.

sdk/lib/html/dartium/html_dartium.dart

Index: sdk/lib/html/dartium/html_dartium.dart
diff --git a/sdk/lib/html/dartium/html_dartium.dart b/sdk/lib/html/dartium/html_dartium.dart
index 8a3b951ff14e861b77c0bb03d3570c58b1af38e2..2e03a71f8d5195667ae5247596546b9513a6592a 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -32608,7 +32608,7 @@ class KeyboardEventController {
   EventTarget _target;
 
   // The distance to shift from upper case alphabet Roman letters to lower case.
-  final int _ROMAN_ALPHABET_OFFSET = "a".charCodes[0] - "A".charCodes[0];
+  final int _ROMAN_ALPHABET_OFFSET = "a".codeUnits[0] - "A".codeUnits[0];
 
   StreamSubscription _keyUpSubscription, _keyDownSubscription,
       _keyPressSubscription;
@@ -32743,8 +32743,8 @@ class KeyboardEventController {
       if (prevEvent._shadowCharCode == event.charCode) {
         return prevEvent.keyCode;
       }
-      if ((event.shiftKey || _capsLockOn) && event.charCode >= "A".charCodes[0]
-          && event.charCode <= "Z".charCodes[0] && event.charCode +
+      if ((event.shiftKey || _capsLockOn) && event.charCode >= "A".codeUnits[0]
+          && event.charCode <= "Z".codeUnits[0] && event.charCode +
           _ROMAN_ALPHABET_OFFSET == prevEvent._shadowCharCode) {
         return prevEvent.keyCode;
       }