--- a/dom/bindings/BindingUtils.h
+++ b/dom/bindings/BindingUtils.h
@@ -473,20 +473,23 @@ public:
 
 // Create a JSObject wrapping "value", for cases when "value" is a
 // non-wrapper-cached object using WebIDL bindings.  "value" must implement a
 // WrapObject() method taking a JSContext and a scope.
 template <class T>
 inline bool
 WrapNewBindingObject(JSContext* cx, JSObject* scope, T* value, JS::Value* vp)
 {
-  JSObject* obj = value->GetWrapper();
-  if (obj && js::GetObjectCompartment(obj) == js::GetObjectCompartment(scope)) {
-    *vp = JS::ObjectValue(*obj);
-    return true;
+  JSObject* obj = value->GetWrapperPreserveColor();
+  if (obj) {
+    xpc_UnmarkNonNullGrayObject(obj);
+    if (js::GetObjectCompartment(obj) == js::GetObjectCompartment(scope)) {
+      *vp = JS::ObjectValue(*obj);
+      return true;
+    }
   }
 
   if (!obj) {
     bool triedToWrap;
     obj = value->WrapObject(cx, scope, &triedToWrap);
     if (!obj) {
       // At this point, obj is null, so just return false.  We could
       // try to communicate triedToWrap to the caller, but in practice

--- a/js/xpconnect/src/xpcpublic.h
+++ b/js/xpconnect/src/xpcpublic.h
@@ -135,26 +135,33 @@ xpc_IsGrayGCThing(void *thing)
 // reachable from an XPConnect root. Implemented in nsXPConnect.cpp.
 extern JSBool
 xpc_GCThingIsGrayCCThing(void *thing);
 
 // Implemented in nsXPConnect.cpp.
 extern void
 xpc_UnmarkGrayGCThingRecursive(void *thing, JSGCTraceKind kind);
 
+// Unmark gray for known-nonnull cases
+MOZ_ALWAYS_INLINE void
+xpc_UnmarkNonNullGrayObject(JSObject *obj)
+{
+    if (xpc_IsGrayGCThing(obj))
+        xpc_UnmarkGrayGCThingRecursive(obj, JSTRACE_OBJECT);
+    else if (JS::IsIncrementalBarrierNeededOnGCThing(obj))
+        js::IncrementalReferenceBarrier(obj);
+}
+
 // Remove the gray color from the given JSObject and any other objects that can
 // be reached through it.
-inline JSObject *
+MOZ_ALWAYS_INLINE JSObject *
 xpc_UnmarkGrayObject(JSObject *obj)
 {
     if (obj) {
-        if (xpc_IsGrayGCThing(obj))
-            xpc_UnmarkGrayGCThingRecursive(obj, JSTRACE_OBJECT);
-        else if (JS::IsIncrementalBarrierNeededOnGCThing(obj))
-            js::IncrementalReferenceBarrier(obj);
+        xpc_UnmarkNonNullGrayObject(obj);
     }
     return obj;
 }
 
 inline JSScript *
 xpc_UnmarkGrayScript(JSScript *script)
 {
     if (script) {