Bug 1581414 - Don't report deprecation warnings after diverging from the recording, r=mccr8.

Differential Revision: https://phabricator.services.mozilla.com/D45960

--HG--
extra : moz-landing-system : lando

dom/bindings/BindingUtils.cpp

@@ -4009,6 +4009,13 @@ void DeprecationWarning(JSContext* aCx, JSObject* aObject,
 void DeprecationWarning(const GlobalObject& aGlobal,
                         Document::DeprecatedOperations aOperation) {
   if (NS_IsMainThread()) {
+    // After diverging from the recording, a replaying process is not able to
+    // report warnings and will be forced to rewind. Avoid reporting warnings
+    // in this case so that the debugger can access deprecated properties.
+    if (recordreplay::HasDivergedFromRecording()) {
+      return;
+    }
+
     nsCOMPtr<nsPIDOMWindowInner> window =
         do_QueryInterface(aGlobal.GetAsSupports());
     if (window && window->GetExtantDoc()) {