Remove use of void** from HttpResponseHeaders::EnumerateHeaderLines

extensions/browser/api/web_request/web_request_event_details.cc

Index: extensions/browser/api/web_request/web_request_event_details.cc
diff --git a/extensions/browser/api/web_request/web_request_event_details.cc b/extensions/browser/api/web_request/web_request_event_details.cc
index 958faea1a50c7688e911fb7771d73d27c6f5af4d..2382dcd654315230b792fbfb7f01692e8585a261 100644
--- a/extensions/browser/api/web_request/web_request_event_details.cc
+++ b/extensions/browser/api/web_request/web_request_event_details.cc
@@ -133,7 +133,7 @@ void WebRequestEventDetails::SetResponseHeaders(
   if (extra_info_spec_ & ExtraInfoSpec::RESPONSE_HEADERS) {
     base::ListValue* headers = new base::ListValue();
     if (response_headers) {
-      void* iter = nullptr;
+      size_t iter = 0;
       std::string name;
       std::string value;
       while (response_headers->EnumerateHeaderLines(&iter, &name, &value))