--- a/js/public/Class.h
+++ b/js/public/Class.h
@@ -4,16 +4,18 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 /* JSClass definition and its component types, plus related interfaces. */
 
 #ifndef js_Class_h
 #define js_Class_h
 
+#include "mozilla/Attributes.h"
+
 #include "jstypes.h"
 
 #include "js/CallArgs.h"
 #include "js/Id.h"
 #include "js/TypeDecls.h"
 
 /*
  * A JSClass acts as a vtable for JS objects that allows JSAPI clients to
@@ -606,22 +608,17 @@ typedef void
         MOZ_ASSERT(cOps && cOps->finalize); \
         cOps->finalize(fop, obj); \
     } \
     void doTrace(JSTracer* trc, JSObject* obj) const { \
         MOZ_ASSERT(cOps && cOps->trace); \
         cOps->trace(trc, obj); \
     }
 
-// XXX: MOZ_NONHEAP_CLASS allows objects to be created statically or on the
-// stack. We actually want to ban stack objects too, but that's currently not
-// possible. So we define JS_STATIC_CLASS to make the intention clearer.
-#define JS_STATIC_CLASS MOZ_NONHEAP_CLASS
-
-struct JS_STATIC_CLASS ClassOps
+struct MOZ_STATIC_CLASS ClassOps
 {
     /* Function pointer members (may be null). */
     JSAddPropertyOp     addProperty;
     JSDeletePropertyOp  delProperty;
     JSEnumerateOp       enumerate;
     JSNewEnumerateOp    newEnumerate;
     JSResolveOp         resolve;
     JSMayResolveOp      mayResolve;
@@ -636,17 +633,17 @@ struct JS_STATIC_CLASS ClassOps
 typedef JSObject* (*ClassObjectCreationOp)(JSContext* cx, JSProtoKey key);
 
 /** Callback for custom post-processing after class initialization via ClassSpec. */
 typedef bool (*FinishClassInitOp)(JSContext* cx, JS::HandleObject ctor,
                                   JS::HandleObject proto);
 
 const size_t JSCLASS_CACHED_PROTO_WIDTH = 6;
 
-struct JS_STATIC_CLASS ClassSpec
+struct MOZ_STATIC_CLASS ClassSpec
 {
     ClassObjectCreationOp createConstructor;
     ClassObjectCreationOp createPrototype;
     const JSFunctionSpec* constructorFunctions;
     const JSPropertySpec* constructorProperties;
     const JSFunctionSpec* prototypeFunctions;
     const JSPropertySpec* prototypeProperties;
     FinishClassInitOp finishInit;
@@ -672,17 +669,17 @@ struct JS_STATIC_CLASS ClassSpec
     }
 
     bool shouldDefineConstructor() const {
         MOZ_ASSERT(defined());
         return !(flags & DontDefineConstructor);
     }
 };
 
-struct JS_STATIC_CLASS ClassExtension
+struct MOZ_STATIC_CLASS ClassExtension
 {
     /**
      * If an object is used as a key in a weakmap, it may be desirable for the
      * garbage collector to keep that object around longer than it otherwise
      * would. A common case is when the key is a wrapper around an object in
      * another compartment, and we want to avoid collecting the wrapper (and
      * removing the weakmap entry) as long as the wrapped object is alive. In
      * that case, the wrapped object is returned by the wrapper's
@@ -711,17 +708,17 @@ struct JS_STATIC_CLASS ClassExtension
      * This is used to compute the nursery promotion rate.
      */
     JSObjectMovedOp objectMovedOp;
 };
 
 #define JS_NULL_CLASS_SPEC  nullptr
 #define JS_NULL_CLASS_EXT   nullptr
 
-struct JS_STATIC_CLASS ObjectOps
+struct MOZ_STATIC_CLASS ObjectOps
 {
     LookupPropertyOp lookupProperty;
     DefinePropertyOp defineProperty;
     HasPropertyOp    hasProperty;
     GetPropertyOp    getProperty;
     SetPropertyOp    setProperty;
     GetOwnPropertyOp getOwnPropertyDescriptor;
     DeletePropertyOp deleteProperty;
@@ -732,17 +729,17 @@ struct JS_STATIC_CLASS ObjectOps
 #define JS_NULL_OBJECT_OPS nullptr
 
 } // namespace js
 
 // Classes, objects, and properties.
 
 typedef void (*JSClassInternal)();
 
-struct JS_STATIC_CLASS JSClassOps
+struct MOZ_STATIC_CLASS JSClassOps
 {
     /* Function pointer members (may be null). */
     JSAddPropertyOp     addProperty;
     JSDeletePropertyOp  delProperty;
     JSEnumerateOp       enumerate;
     JSNewEnumerateOp    newEnumerate;
     JSResolveOp         resolve;
     JSMayResolveOp      mayResolve;
@@ -862,17 +859,17 @@ static const uint32_t JSCLASS_CACHED_PRO
                                           & JSCLASS_CACHED_PROTO_MASK))
 
 // Initializer for unused members of statically initialized JSClass structs.
 #define JSCLASS_NO_INTERNAL_MEMBERS     {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}
 #define JSCLASS_NO_OPTIONAL_MEMBERS     0,0,0,0,0,JSCLASS_NO_INTERNAL_MEMBERS
 
 namespace js {
 
-struct JS_STATIC_CLASS Class
+struct MOZ_STATIC_CLASS Class
 {
     JS_CLASS_MEMBERS(js::ClassOps, FreeOp);
     const ClassSpec* spec;
     const ClassExtension* ext;
     const ObjectOps* oOps;
 
     /*
      * Objects of this class aren't native objects. They don't have Shapes that