diff --git a/js/src/vm/Debugger.cpp b/js/src/vm/Debugger.cpp
index 409fccc0dab0..9025e1945f33 100644
--- a/js/src/vm/Debugger.cpp
+++ b/js/src/vm/Debugger.cpp
@@ -809,6 +809,63 @@ Debugger::unwrapDebuggeeValue(JSContext *cx, MutableHandleValue vp)
     return true;
 }
 
+/*
+ * Convert Debugger.Objects in desc to debuggee values.
+ * Reject non-callable getters and setters.
+ */
+static bool
+CheckArgCompartment(JSContext *cx, JSObject *obj, HandleValue v,
+                    const char *methodname, const char *propname)
+{
+    if (v.isObject() && v.toObject().compartment() != obj->compartment()) {
+        JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_DEBUG_COMPARTMENT_MISMATCH,
+                             methodname, propname);
+        return false;
+    }
+    return true;
+}
+
+bool
+Debugger::unwrapPropDescInto(JSContext *cx, HandleObject obj, Handle<PropDesc> wrapped,
+                             MutableHandle<PropDesc> unwrapped)
+{
+    MOZ_ASSERT(!wrapped.isUndefined());
+
+    unwrapped.set(wrapped);
+
+    if (unwrapped.hasValue()) {
+        RootedValue value(cx, unwrapped.value());
+        if (!unwrapDebuggeeValue(cx, &value) ||
+            !CheckArgCompartment(cx, obj, value, "defineProperty", "value"))
+        {
+            return false;
+        }
+        unwrapped.setValue(value);
+    }
+
+    if (unwrapped.hasGet()) {
+        RootedValue get(cx, unwrapped.getterValue());
+        if (!unwrapDebuggeeValue(cx, &get) ||
+            !CheckArgCompartment(cx, obj, get, "defineProperty", "get"))
+        {
+            return false;
+        }
+        unwrapped.setGetter(get);
+    }
+
+    if (unwrapped.hasSet()) {
+        RootedValue set(cx, unwrapped.setterValue());
+        if (!unwrapDebuggeeValue(cx, &set) ||
+            !CheckArgCompartment(cx, obj, set, "defineProperty", "set"))
+        {
+            return false;
+        }
+        unwrapped.setSetter(set);
+    }
+
+    return true;
+}
+
 JSTrapStatus
 Debugger::handleUncaughtExceptionHelper(Maybe<AutoCompartment> &ac,
                                         MutableHandleValue *vp, bool callHook)
@@ -5262,7 +5319,7 @@ DebuggerObject_defineProperty(JSContext *cx, unsigned argc, Value *vp)
         return false;
     desc.clearPd();
 
-    if (!desc.get().unwrapDebuggerObjectsInto(cx, dbg, obj, desc.address()))
+    if (!dbg->unwrapPropDescInto(cx, obj, desc, &desc))
         return false;
     if (!desc.checkGetter(cx) || !desc.checkSetter(cx))
         return false;
@@ -5306,7 +5363,10 @@ DebuggerObject_defineProperties(JSContext *cx, unsigned argc, Value *vp)
     for (size_t i = 0; i < n; i++) {
         if (!unwrappedDescs.append())
             return false;
-        if (!descs[i].unwrapDebuggerObjectsInto(cx, dbg, obj, &unwrappedDescs[i]))
+        Handle<PropDesc> wrapped = Handle<PropDesc>::fromMarkedLocation(&descs[i]);
+        MutableHandle<PropDesc> unwrapped =
+            MutableHandle<PropDesc>::fromMarkedLocation(&unwrappedDescs[i]);
+        if (!dbg->unwrapPropDescInto(cx, obj, wrapped, unwrapped))
             return false;
         if (!unwrappedDescs[i].checkGetter(cx) || !unwrappedDescs[i].checkSetter(cx))
             return false;
diff --git a/js/src/vm/Debugger.h b/js/src/vm/Debugger.h
index df6da16ec406..0bc28b238ea0 100644
--- a/js/src/vm/Debugger.h
+++ b/js/src/vm/Debugger.h
@@ -506,6 +506,8 @@ class Debugger : private mozilla::LinkedListElement<Debugger>
      * happens in the target compartment--rotational symmetry.)
      */
     bool unwrapDebuggeeValue(JSContext *cx, MutableHandleValue vp);
+    bool unwrapPropDescInto(JSContext *cx, HandleObject obj, Handle<PropDesc> wrapped,
+                            MutableHandle<PropDesc> unwrapped);
 
     /*
      * Store the Debugger.Frame object for frame in *vp.
diff --git a/js/src/vm/ObjectImpl.cpp b/js/src/vm/ObjectImpl.cpp
index 1538f04af933..703ea069d09d 100644
--- a/js/src/vm/ObjectImpl.cpp
+++ b/js/src/vm/ObjectImpl.cpp
@@ -59,63 +59,6 @@ PropDesc::checkSetter(JSContext *cx)
     return true;
 }
 
-static bool
-CheckArgCompartment(JSContext *cx, JSObject *obj, HandleValue v,
-                    const char *methodname, const char *propname)
-{
-    if (v.isObject() && v.toObject().compartment() != obj->compartment()) {
-        JS_ReportErrorNumber(cx, js_GetErrorMessage, nullptr, JSMSG_DEBUG_COMPARTMENT_MISMATCH,
-                             methodname, propname);
-        return false;
-    }
-    return true;
-}
-
-/*
- * Convert Debugger.Objects in desc to debuggee values.
- * Reject non-callable getters and setters.
- */
-bool
-PropDesc::unwrapDebuggerObjectsInto(JSContext *cx, Debugger *dbg, HandleObject obj,
-                                    PropDesc *unwrapped) const
-{
-    MOZ_ASSERT(!isUndefined());
-
-    *unwrapped = *this;
-
-    if (unwrapped->hasValue()) {
-        RootedValue value(cx, unwrapped->value_);
-        if (!dbg->unwrapDebuggeeValue(cx, &value) ||
-            !CheckArgCompartment(cx, obj, value, "defineProperty", "value"))
-        {
-            return false;
-        }
-        unwrapped->value_ = value;
-    }
-
-    if (unwrapped->hasGet()) {
-        RootedValue get(cx, unwrapped->get_);
-        if (!dbg->unwrapDebuggeeValue(cx, &get) ||
-            !CheckArgCompartment(cx, obj, get, "defineProperty", "get"))
-        {
-            return false;
-        }
-        unwrapped->get_ = get;
-    }
-
-    if (unwrapped->hasSet()) {
-        RootedValue set(cx, unwrapped->set_);
-        if (!dbg->unwrapDebuggeeValue(cx, &set) ||
-            !CheckArgCompartment(cx, obj, set, "defineProperty", "set"))
-        {
-            return false;
-        }
-        unwrapped->set_ = set;
-    }
-
-    return true;
-}
-
 /*
  * Rewrap *idp and the fields of *desc for the current compartment.  Also:
  * defining a property on a proxy requires pd_ to contain a descriptor object,
diff --git a/js/src/vm/PropDesc.h b/js/src/vm/PropDesc.h
index bea886625635..1beae907a1e8 100644
--- a/js/src/vm/PropDesc.h
+++ b/js/src/vm/PropDesc.h
@@ -12,8 +12,6 @@
 
 namespace js {
 
-class Debugger;
-
 static inline JSPropertyOp
 CastAsPropertyOp(JSObject *object)
 {
@@ -182,6 +180,11 @@ struct PropDesc {
         MOZ_ASSERT(hasValue());
         return HandleValue::fromMarkedLocation(&value_);
     }
+    void setValue(const Value &value) {
+        MOZ_ASSERT(!isUndefined());
+        value_ = value;
+        hasValue_ = true;
+    }
 
     JSObject * getterObject() const {
         MOZ_ASSERT(!isUndefined());
@@ -205,6 +208,17 @@ struct PropDesc {
         return HandleValue::fromMarkedLocation(&set_);
     }
 
+    void setGetter(const Value &getter) {
+        MOZ_ASSERT(!isUndefined());
+        get_ = getter;
+        hasGet_ = true;
+    }
+    void setSetter(const Value &setter) {
+        MOZ_ASSERT(!isUndefined());
+        set_ = setter;
+        hasSet_ = true;
+    }
+
     /*
      * Unfortunately the values produced by these methods are used such that
      * we can't assert anything here.  :-(
@@ -224,9 +238,6 @@ struct PropDesc {
     bool checkGetter(JSContext *cx);
     bool checkSetter(JSContext *cx);
 
-    bool unwrapDebuggerObjectsInto(JSContext *cx, Debugger *dbg, HandleObject obj,
-                                   PropDesc *unwrapped) const;
-
     bool wrapInto(JSContext *cx, HandleObject obj, const jsid &id, jsid *wrappedId,
                   PropDesc *wrappedDesc) const;
 };
@@ -299,6 +310,16 @@ class MutablePropDescOperations : public PropDescOperations<Outer>
         return desc()->makeObject(cx);
     }
 
+    void setValue(const Value &value) {
+        desc()->setValue(value);
+    }
+    void setGetter(const Value &getter) {
+        desc()->setGetter(getter);
+    }
+    void setSetter(const Value &setter) {
+        desc()->setSetter(setter);
+    }
+
     void setUndefined() { desc()->setUndefined(); }
     void clearPd() { desc()->clearPd(); }
 };