Bug 1066340 - Use an AutoEntryScript in nsFrameMessageManager::ReceiveMessage. r=smaug

content/base/src/nsFrameMessageManager.cpp

@@ -925,7 +925,6 @@ nsFrameMessageManager::ReceiveMessage(nsISupports* aTarget,
                                       nsIPrincipal* aPrincipal,
                                       InfallibleTArray<nsString>* aJSONRetVal)
 {
-  AutoSafeJSContext cx;
   nsAutoTObserverArray<nsMessageListenerInfo, 1>* listeners =
     mListeners.Get(aMessage);
   if (listeners) {
@@ -956,11 +955,23 @@ nsFrameMessageManager::ReceiveMessage(nsISupports* aTarget,
       if (!wrappedJS) {
         continue;
       }
-      JS::Rooted<JSObject*> object(cx, wrappedJS->GetJSObject());
-      if (!object) {
+
+      if (!wrappedJS->GetJSObject()) {
         continue;
       }
-      JSAutoCompartment ac(cx, object);
+
+      // Note - The ergonomics here will get a lot better with bug 971673:
+      //
+      // AutoEntryScript aes;
+      // if (!aes.Init(wrappedJS->GetJSObject())) {
+      //   continue;
+      // }
+      // JSContext* cx = aes.cx();
+      nsIGlobalObject* nativeGlobal =
+        xpc::GetNativeForGlobal(js::GetGlobalForObjectCrossCompartment(wrappedJS->GetJSObject()));
+      AutoEntryScript aes(nativeGlobal);
+      JSContext* cx = aes.cx();
+      JS::Rooted<JSObject*> object(cx, wrappedJS->GetJSObject());
 
       // The parameter for the listener function.
       JS::Rooted<JSObject*> param(cx,

content/base/test/chrome/cpows_child.js

@@ -9,6 +9,7 @@ var is_remote;
 (function start() {
     [is_remote] = sendSyncMessage("cpows:is_remote");
     parent_test();
+    error_reporting_test();
     dom_test();
     xray_test();
     compartment_test();
@@ -89,6 +90,10 @@ function parent_test()
   sendSyncMessage("cpows:parent_test", {}, {func: f});
 }
 
+function error_reporting_test() {
+  sendSyncMessage("cpows:error_reporting_test", {}, {});
+}
+
 function dom_test()
 {
   let element = content.document.createElement("div");

content/base/test/chrome/cpows_parent.xul

@@ -33,7 +33,12 @@
     }
 
     // Make sure that an error in this file actually causes the test to fail.
+    var gReceivedErrorProbe = false;
     window.onerror = function (msg, url, line) {
+      if (/Test Error Probe/.test(msg)) {
+        gReceivedErrorProbe = true;
+        return;
+      }
       ok(false, "Error while executing: \n" + msg + "\n" + url + ":" + line);
     };
 
@@ -175,6 +180,11 @@
       savedMM.sendAsyncMessage("cpows:from_parent", {}, {obj: obj});
     }
 
+    // Make sure errors in this file actually hit window.onerror.
+    function recvErrorReportingTest(message) {
+      throw "Test Error Probe";
+    }
+
     let savedElement = null;
     function recvDomTest(message) {
       savedElement = message.objects.element;
@@ -271,6 +281,7 @@
       mm.addMessageListener("cpows:done", recvDoneMessage);
       mm.addMessageListener("cpows:fail", recvFailMessage);
       mm.addMessageListener("cpows:parent_test", recvParentTest);
+      mm.addMessageListener("cpows:error_reporting_test", recvErrorReportingTest);
       mm.addMessageListener("cpows:dom_test", recvDomTest);
       mm.addMessageListener("cpows:dom_test_after_gc", recvDomTestAfterGC);
       mm.addMessageListener("cpows:xray_test", recvXrayTest);
@@ -285,6 +296,7 @@
     }
 
     function finish() {
+      ok(gReceivedErrorProbe, "Should have reported error probe");
       opener.setTimeout("done()", 0);
       window.close();
     }