--- a/js/ipc/JavaScriptChild.cpp
+++ b/js/ipc/JavaScriptChild.cpp
@@ -127,19 +127,19 @@ JavaScriptChild::fail(JSContext *cx, Ret
     // that would crash.
     JS_ClearPendingException(cx);
 
     if (JS_IsStopIteration(exn)) {
         *rs = ReturnStatus(ReturnStopIteration());
         return true;
     }
 
-    if (!toVariant(cx, exn, &rs->get_ReturnException().exn()))
-        return true;
-
+    // If this fails, we still don't want to exit. Just return an invalid
+    // exception.
+    (void) toVariant(cx, exn, &rs->get_ReturnException().exn());
     return true;
 }
 
 bool
 JavaScriptChild::ok(ReturnStatus *rs)
 {
     *rs = ReturnStatus(ReturnSuccess());
     return true;
@@ -372,17 +372,17 @@ JavaScriptChild::AnswerGet(const ObjectI
         return false;
 
     JSAutoCompartment comp(cx, obj);
 
     RootedId internedId(cx);
     if (!convertGeckoStringToId(cx, id, &internedId))
         return fail(cx, rs);
 
-    JS::Rooted<JS::Value> val(cx);
+    JS::RootedValue val(cx);
     if (!JS_ForwardGetPropertyTo(cx, obj, internedId, receiver, &val))
         return fail(cx, rs);
 
     if (!toVariant(cx, val, result))
         return fail(cx, rs);
 
     return ok(rs);
 }
@@ -532,17 +532,17 @@ JavaScriptChild::AnswerCall(const Object
         if (!vals.append(v))
             return fail(cx, rs);
     }
 
     // Copy the outparams. If any outparam is already set to a void_t, we
     // treat this as the outparam never having been set.
     for (size_t i = 0; i < vals.length(); i++) {
         JSVariant variant;
-        if (!toVariant(cx, vals[i], &variant))
+        if (!toVariant(cx, vals.handleAt(i), &variant))
             return fail(cx, rs);
         outparams->ReplaceElementAt(i, JSParam(variant));
     }
 
     return ok(rs);
 }
 
 bool

--- a/js/ipc/JavaScriptShared.cpp
+++ b/js/ipc/JavaScriptShared.cpp
@@ -147,17 +147,17 @@ JavaScriptShared::convertGeckoStringToId
     RootedString str(cx, JS_NewUCStringCopyN(cx, from.BeginReading(), from.Length()));
     if (!str)
         return false;
 
     return JS_ValueToId(cx, StringValue(str), to.address());
 }
 
 bool
-JavaScriptShared::toVariant(JSContext *cx, jsval from, JSVariant *to)
+JavaScriptShared::toVariant(JSContext *cx, JS::HandleValue from, JSVariant *to)
 {
     switch (JS_TypeOfValue(cx, from)) {
       case JSTYPE_VOID:
         *to = void_t();
         return true;
 
       case JSTYPE_NULL:
       {

--- a/js/ipc/JavaScriptShared.h
+++ b/js/ipc/JavaScriptShared.h
@@ -86,17 +86,17 @@ class JavaScriptShared
 
     static const uint32_t OBJECT_EXTRA_BITS  = 1;
     static const uint32_t OBJECT_IS_CALLABLE = (1 << 0);
 
     bool Unwrap(JSContext *cx, const InfallibleTArray<CpowEntry> &aCpows, JSObject **objp);
     bool Wrap(JSContext *cx, JS::HandleObject aObj, InfallibleTArray<CpowEntry> *outCpows);
 
   protected:
-    bool toVariant(JSContext *cx, jsval from, JSVariant *to);
+    bool toVariant(JSContext *cx, JS::HandleValue from, JSVariant *to);
     bool toValue(JSContext *cx, const JSVariant &from, JS::MutableHandleValue to);
     bool fromDescriptor(JSContext *cx, JS::Handle<JSPropertyDescriptor> desc, PPropertyDescriptor *out);
     bool toDescriptor(JSContext *cx, const PPropertyDescriptor &in,
                       JS::MutableHandle<JSPropertyDescriptor> out);
     bool convertIdToGeckoString(JSContext *cx, JS::HandleId id, nsString *to);
     bool convertGeckoStringToId(JSContext *cx, const nsString &from, JS::MutableHandleId id);
 
     bool toValue(JSContext *cx, const JSVariant &from, jsval *to) {