Use JSON.stringify to serialize debugger messages

test/mjsunit/mirror-boolean.js

 // Copyright 2008 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 14 matching lines @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Flags: --expose-debug-as debug
 // Test the mirror object for boolean values
 
 function testBooleanMirror(b) {
   // Create mirror and JSON representation.
   var mirror = debug.MakeMirror(b);
   var serializer = debug.MakeMirrorSerializer();
-  var json = serializer.serializeValue(mirror);
+  var json = JSON.stringify(serializer.serializeValue(mirror));
 
   // Check the mirror hierachy.
   assertTrue(mirror instanceof debug.Mirror);
   assertTrue(mirror instanceof debug.ValueMirror);
   assertTrue(mirror instanceof debug.BooleanMirror);
 
   // Check the mirror properties.
   assertTrue(mirror.isBoolean());
   assertEquals('boolean', mirror.type());
   assertTrue(mirror.isPrimitive());
 
   // Test text representation
   assertEquals(b ? 'true' : 'false', mirror.toText());
 
   // Parse JSON representation and check.
   var fromJSON = eval('(' + json + ')');
   assertEquals('boolean', fromJSON.type, json);
   assertEquals(b, fromJSON.value, json);
 }
 
 
 // Test all boolean values.
 testBooleanMirror(true);
 testBooleanMirror(false);