Bug 1474541 part 2 - Assert we don't pass cross-compartment wrappers to AutoEntryScript. r=bz

dom/script/ScriptSettings.cpp

@@ -670,6 +670,7 @@ AutoEntryScript::AutoEntryScript(JSObject* aObject,
                                  bool aIsMainThread)
   : AutoEntryScript(xpc::NativeGlobal(aObject), aReason, aIsMainThread)
 {
+  MOZ_ASSERT(!js::IsCrossCompartmentWrapper(aObject));
 }
 
 AutoEntryScript::~AutoEntryScript()

dom/script/ScriptSettings.h

@@ -322,7 +322,10 @@ public:
                   const char *aReason,
                   bool aIsMainThread = NS_IsMainThread());
 
-  AutoEntryScript(JSObject* aObject, // Any object from the relevant global
+  // aObject can be any object from the relevant global. It must not be a
+  // cross-compartment wrapper because CCWs are not associated with a single
+  // global.
+  AutoEntryScript(JSObject* aObject,
                   const char *aReason,
                   bool aIsMainThread = NS_IsMainThread());