Better mangling in frog for fixing parts of issue 1837.

frog/member.dart

Index: frog/member.dart
===================================================================
--- frog/member.dart	(revision 4594)
+++ frog/member.dart	(working copy)
@@ -89,7 +89,11 @@
 
   Member(String name, Type declaringType)
       : this.declaringType = declaringType,
-        super(name, declaringType);
+        super(name, declaringType) {
+    if (_jsname != null && declaringType.isTop) {
+      _jsname = JsNames.getValid(_jsname);
+    }
+  }
 
   abstract bool get isStatic();
   abstract Type get returnType();
@@ -1148,7 +1152,7 @@
       } else if (args.length == 1 && args.values[0].type.isNum) {
         if (name == ':truncdiv' || name == ':mod') {
           world.gen.corejs.useOperator(name);
-          code = '\$$jsname(${target.code}, ${argsCode[0]})';
+          code = '$jsname\$(${target.code}, ${argsCode[0]})';
         } else {
           var op = TokenKind.rawOperatorFromMethod(name);
           code = '${target.code} $op ${argsCode[0]}';
@@ -1197,7 +1201,7 @@
       world.gen.corejs.useOperator(name);
       // TODO(jimhug): Should be able to use faster path sometimes here!
       return new Value(inferredResult,
-          '\$$jsname(${target.code}, ${argsCode[0]})', node.span);
+          '$jsname\$(${target.code}, ${argsCode[0]})', node.span);
     }
 
     if (isCallMethod) {
@@ -1214,7 +1218,7 @@
     } else {
       world.gen.corejs.useOperator(name);
       var argsString = argsCode.length == 0 ? '' : ', ${argsCode[0]}';
-      return new Value(returnType, '\$$jsname(${target.code}${argsString})',
+      return new Value(returnType, '$jsname\$(${target.code}${argsString})',
         node.span);
     }