Return null from stringValue and call slowToString() instead of toString().

dart/frog/leg/namer.dart

 // Copyright (c) 2011, 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.
 
 /**
  * Assigns JavaScript identifiers to Dart variables, class-names and members.
  */
 class Namer {
   final Compiler compiler;
 
@@ skipping 21 matching lines @@
   final String ISOLATE = "Isolate";
 
 
   String closureInvocationName(Selector selector) {
     // TODO(floitsch): mangle, while not conflicting with instance names.
     return instanceMethodInvocationName(CLOSURE_INVOCATION_NAME, selector);
   }
 
   String instanceMethodName(SourceString name, int arity) {
     // TODO(floitsch): mangle, while preserving uniqueness.
-    return '$name\$$arity';
+    return '${name.slowToString()}\$$arity';
   }
 
   String instanceMethodInvocationName(SourceString name, Selector selector) {
     // TODO(floitsch): mangle, while preserving uniqueness.
     StringBuffer buffer = new StringBuffer();
     List<SourceString> names = selector.getOrderedNamedArguments();
     for (SourceString name in names) {
-      buffer.add('\$$name');
+      buffer.add(@'$');
+      name.printOn(buffer);
     }
-    return '$name\$${selector.argumentCount}$buffer';
+    return '${name.slowToString()}\$${selector.argumentCount}$buffer';
   }
 
   String instanceFieldName(SourceString name) {
-    return '$name';
+    return name.slowToString();
   }
 
   String setterName(SourceString name) {
-    return 'set\$$name';
+    return 'set\$${name.slowToString()}';
   }
 
   String getterName(SourceString name) {
-    return 'get\$$name';
+    return 'get\$${name.slowToString()}';
   }
 
   String getFreshGlobalName(String proposedName) {
     int usedCount = usedGlobals[proposedName];
     if (usedCount === null) {
       // No element with this name has been used before.
       usedGlobals[proposedName] = 1;
       return proposedName;
     } else {
       // Not the first time we see this name. Append a number to make it unique.
@@ skipping 19 matching lines @@
           element.name, functionElement.parameterCount(compiler));
     } else {
       // TODO(floitsch): deal with named constructors.
       String name;
       if (element.kind == ElementKind.GETTER) {
         name = getterName(element.name);
       } else if (element.kind == ElementKind.SETTER) {
         name = setterName(element.name);
       } else if (element.kind == ElementKind.FUNCTION) {
         FunctionElement functionElement = element;
-        name = '${element.name}\$${functionElement.parameterCount(compiler)}';
+        name = element.name.slowToString();
+        name = '$name\$${functionElement.parameterCount(compiler)}';
       } else {
-        name = '${element.name}';
+        name = '${element.name.slowToString()}';
       }
       // Prefix the name with '$' if it is reserved.
       if (jsReserved.contains(name)) {
         name = "\$$name";
         assert(!jsReserved.contains(name));
       }
       return name;
     }
   }
 
@@ skipping 68 matching lines @@
   }
 
   String isolateBailoutAccess(Element element) {
     return '${isolateAccess(element)}\$bailout';
   }
 
   String operatorIs(ClassElement element) {
     return 'is\$${getName(element)}';
   }
 }