Bug 1576787 - Handle RemoteObjectProxies in instanceof r=bzbarsky

Differential Revision: https://phabricator.services.mozilla.com/D43559

--HG--
extra : moz-landing-system : lando

dom/bindings/BindingUtils.cpp

@@ -2461,6 +2461,11 @@ bool InterfaceHasInstance(JSContext* cx, unsigned argc, JS::Value* vp) {
     return true;
   }
 
+  if (IsRemoteObjectProxy(instance, clasp->mPrototypeID)) {
+    args.rval().setBoolean(true);
+    return true;
+  }
+
   return CallOrdinaryHasInstance(cx, args);
 }
 

js/xpconnect/tests/mochitest/mochitest.ini

@@ -89,7 +89,6 @@ fail-if = fission # Bug 1573621: window.location access after cross-origin navig
 [test_bug862380.html]
 [test_bug865260.html]
 [test_bug870423.html]
-fail-if = fission # isinstance hooks for remote object proxies.
 [test_bug871887.html]
 [test_bug912322.html]
 [test_bug916945.html]

js/xpconnect/tests/mochitest/test_bug870423.html

@@ -16,6 +16,7 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=870423
   function go() {
     var sowin = $('soifr').contentWindow;
     var xowin = $('xoifr').contentWindow;
+    var xosswin = $('xossifr').contentWindow;
 
     check(window, sowin, 'HTMLBodyElement', function(win) { return win.document.body; });
     check(window, sowin, 'HTMLDocument', function(win) { return win.document; });
@@ -25,6 +26,10 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=870423
     ok(xowin instanceof Window, "Cross-origin instanceof should work");
     ok(xowin.location instanceof Location, "Cross-origin instanceof should work");
 
+    // cross-origin same-site.
+    ok(xosswin instanceof Window, "Cross-origin instanceof should work");
+    ok(xosswin.location instanceof Location, "Cross-origin instanceof should work");
+
     SimpleTest.finish();
   }
 
@@ -45,6 +50,8 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=870423
 </div>
 <iframe id="soifr" src="file_empty.html"></iframe>
 <iframe id="xoifr" src="http://example.org/tests/js/xpconnect/tests/mochitest/file_empty.html"></iframe>
+<!-- cross origin, same site -->
+<iframe id="xossifr" src="//test1.mochi.test:8888/tests/js/xpconnect/tests/mochitest/file_empty.html"></iframe>
 <pre id="test">
 </pre>
 </body>