Implement Mirror object for Symbols.

test/mjsunit/es6/mirror-symbols.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Flags: --expose-debug-as debug --harmony-symbols
+// Test the mirror object for symbols.
+
+function testSymbolMirror(symbol, name) {
+  // Create mirror and JSON representation.
+  var mirror = debug.MakeMirror(symbol);
+  var serializer = debug.MakeMirrorSerializer();
+  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.SymbolMirror);
+
+  // Check the mirror properties.
+  assertTrue(mirror.isSymbol());
+  assertEquals(name, mirror.name());
+  assertEquals('symbol', mirror.type());
+  assertTrue(mirror.isPrimitive());
+  assertEquals('Symbol "' + name + '"', mirror.toText());
+  assertSame(symbol, mirror.value());
+
+  // Parse JSON representation and check.
+  var fromJSON = eval('(' + json + ')');
+  assertEquals('symbol', fromJSON.type);
+  assertEquals(name, fromJSON.name);
+}
+
+// Test a number of different symbols.
+testSymbolMirror(Symbol("a"), "a");
+testSymbolMirror(Symbol(12), "12");
+testSymbolMirror(Symbol.for("b"), "b");
+testSymbolMirror(Symbol(), undefined);