--- a/dom/bindings/BindingUtils.cpp
+++ b/dom/bindings/BindingUtils.cpp
@@ -116,17 +116,17 @@ ErrorResult::ClearMessage()
 {
   if (IsTypeError()) {
     delete mMessage;
     mMessage = nullptr;
   }
 }
 
 void
-ErrorResult::ThrowJSException(JSContext* cx, JS::Value exn)
+ErrorResult::ThrowJSException(JSContext* cx, JS::Handle<JS::Value> exn)
 {
   MOZ_ASSERT(mMightHaveUnreportedJSException,
              "Why didn't you tell us you planned to throw a JS exception?");
 
   if (IsTypeError()) {
     delete mMessage;
   }
 

--- a/dom/bindings/CallbackObject.cpp
+++ b/dom/bindings/CallbackObject.cpp
@@ -140,18 +140,18 @@ CallbackObject::CallSetup::~CallSetup()
   // errors on it, unless we were told to re-throw them.
   if (mCx) {
     bool dealtWithPendingException = false;
     if (mExceptionHandling == eRethrowExceptions) {
       // Restore the old context options
       JS_SetOptions(mCx, mSavedJSContextOptions);
       mErrorResult.MightThrowJSException();
       if (JS_IsExceptionPending(mCx)) {
-        JS::Value exn;
-        if (JS_GetPendingException(mCx, &exn)) {
+        JS::Rooted<JS::Value> exn(mCx);
+        if (JS_GetPendingException(mCx, exn.address())) {
           mErrorResult.ThrowJSException(mCx, exn);
           JS_ClearPendingException(mCx);
           dealtWithPendingException = true;
         }
       }
     }
 
     if (!dealtWithPendingException) {

--- a/dom/bindings/ErrorResult.h
+++ b/dom/bindings/ErrorResult.h
@@ -61,17 +61,17 @@ public:
   void ClearMessage();
   bool IsTypeError() const { return ErrorCode() == NS_ERROR_TYPE_ERR; }
 
   // Facilities for throwing a preexisting JS exception value via this
   // ErrorResult.  The contract is that any code which might end up calling
   // ThrowJSException() must call MightThrowJSException() even if no exception
   // is being thrown.  Code that would call ReportJSException as needed must
   // first call WouldReportJSException even if this ErrorResult has not failed.
-  void ThrowJSException(JSContext* cx, JS::Value exn);
+  void ThrowJSException(JSContext* cx, JS::Handle<JS::Value> exn);
   void ReportJSException(JSContext* cx);
   bool IsJSException() const { return ErrorCode() == NS_ERROR_DOM_JS_EXCEPTION; }
   void MOZ_ALWAYS_INLINE MightThrowJSException()
   {
 #ifdef DEBUG
     mMightHaveUnreportedJSException = true;
 #endif
   }