Use createV8Entry() and toV8Value() with context and isolate defined in WebDOMFileSystem.

content/renderer/pepper/resource_converter.cc

Index: content/renderer/pepper/resource_converter.cc
diff --git a/content/renderer/pepper/resource_converter.cc b/content/renderer/pepper/resource_converter.cc
index 476e3d37413c5bd4e6726ee6a4271e16d6564217..4b0c9c990efaaa327bad5d983a47b63ce19dace2 100644
--- a/content/renderer/pepper/resource_converter.cc
+++ b/content/renderer/pepper/resource_converter.cc
@@ -141,7 +141,8 @@ bool ResourceHostToDOMFileSystem(
       blink::WebString::fromUTF8(name),
       root_url,
       blink::WebDOMFileSystem::SerializableTypeSerializable);
-  *dom_file_system = web_dom_file_system.toV8Value();
+  *dom_file_system =
+      web_dom_file_system.toV8Value(context->Global(), context->GetIsolate());
   return true;
 }