[Extensions] Handle null ScriptContexts in GetModuleSystem()

extensions/renderer/v8_context_native_handler.cc

Index: extensions/renderer/v8_context_native_handler.cc
diff --git a/extensions/renderer/v8_context_native_handler.cc b/extensions/renderer/v8_context_native_handler.cc
index 85c3c3794ea2c29a2b2968304f3fd7bd160c9d6c..a24be1708cc284848f25b917dcacd0c8f2fe8274 100644
--- a/extensions/renderer/v8_context_native_handler.cc
+++ b/extensions/renderer/v8_context_native_handler.cc
@@ -48,7 +48,7 @@ void V8ContextNativeHandler::GetModuleSystem(
   CHECK(args[0]->IsObject());
   ScriptContext* context = ScriptContextSet::GetContextByObject(
       v8::Local<v8::Object>::Cast(args[0]));
-  if (blink::WebFrame::scriptCanAccess(context->web_frame()))
+  if (context && blink::WebFrame::scriptCanAccess(context->web_frame()))
     args.GetReturnValue().Set(context->module_system()->NewInstance());
 }