Newest Electron is based on 51.0.2704.63

Please update to latest Chrome stable 51.0.2704.79 which was released a week ago and fixes multiple security issues:

 http://googlechromereleases.blogspot.com/2016/06/stable-channel-update.html

[$7500][613266] High CVE-2016-1697: Cross-origin bypass in Blink. Credit to Mariusz Mlynski.
[$3500][607939] Medium CVE-2016-1699: Parameter sanitization failure in DevTools. Credit to Gregory Panakkal.
[$1000][608101] Medium CVE-2016-1701: Use-after-free in Autofill. Credit to Rob Wu.
[$1000][609260] Medium CVE-2016-1702: Out-of-bounds read in Skia. Credit to cloudfuzzer.
[616539] CVE-2016-1703: Various fixes from internal audits, fuzzing and other initiatives.

See also the discussion about handling security updates in #5210 

atom/common/chrome_version.h
#ifndef ATOM_COMMON_CHROME_VERSION_H_
#define ATOM_COMMON_CHROME_VERSION_H_
#define CHROME_VERSION_STRING "51.0.2704.63"
#define CHROME_VERSION "v" CHROME_VERSION_STRING
#endif