diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/debug/Object-class.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/debug/Object-class.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,26 @@
+// Basic tests for Debugger.Object.prototype.class.
+var g = newGlobal();
+var dbg = new Debugger(g);
+var hits = 0;
+g.eval('function f() { debugger; }');
+
+dbg.onDebuggerStatement = function (frame) {
+    var arr = frame.arguments;
+    assertEq(arr[0].class, "Object");
+    assertEq(arr[1].class, "Array");
+    assertEq(arr[2].class, "Function");
+    assertEq(arr[3].class, "Date");
+    assertEq(arr[4].class, "Object");
+    assertEq(arr[5].class, "Function");
+    assertEq(arr[6].class, "Date");
+    hits++;
+};
+g.f(Object.prototype, [], eval, new Date,
+    Proxy.create({}), Proxy.createFunction({}, eval), new Proxy(new Date, {}));
+assertEq(hits, 1);
+
+// Debugger.Object.prototype.class should see through cross-compartment
+// wrappers.
+g.eval('f(Object.prototype, [], eval, new Date,\
+          Proxy.create({}), Proxy.createFunction({}, f), new Proxy(new Date, {}));');
+assertEq(hits, 2);