Fix DCHECK in debug build when navigating to an unknown chrome://theme/ URL.

net/url_request/url_request_job.h

Index: net/url_request/url_request_job.h
diff --git a/net/url_request/url_request_job.h b/net/url_request/url_request_job.h
index b93ff45d633c9330beaeb77f4772d3d8d5486245..d63793ec88fdad9c9631c0b2217333b58e2f9b64 100644
--- a/net/url_request/url_request_job.h
+++ b/net/url_request/url_request_job.h
@@ -348,6 +348,7 @@ class NET_EXPORT URLRequestJob : public base::PowerObserver {
   // Completion callback for raw reads. See |ReadRawData| for details.
   // |bytes_read| is either >= 0 to indicate a successful read and count of
   // bytes read, or < 0 to indicate an error.
+  // On return, |this| may be deleted.
   void ReadRawDataComplete(int bytes_read);
 
   // The request that initiated this job. This value will never be nullptr.