Remove deprecated string features.

sdk/lib/_internal/compiler/implementation/js_backend/emitter.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.
 
 part of js_backend;
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
@@ skipping 2368 matching lines @@
 
     jsAst.Expression isNotObject(String variable) {
       return js[variable].typeof.equals(js.string('object')).not;
     }
 
     jsAst.Expression isInt(String variable) {
       jsAst.Expression receiver = js[variable];
       return isNumber(variable).binary('&&',
           js['Math']['floor'](receiver).equals(receiver));
     }
-    
+
     jsAst.Expression tripleShiftZero(jsAst.Expression receiver) {
       return receiver.binary('>>>', js.toExpression(0));
     }
 
     if (selector.isOperator()) {
       String name = selector.name.stringValue;
       if (name == '==') {
         // Unfolds to:
         // [: if (receiver == null) return a0 == null;
         //    if (typeof receiver != 'object') {
@@ skipping 306 matching lines @@
 """;
 const String HOOKS_API_USAGE = """
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;