Chrome Version       : Version 63.0.3239.132 (Official Build) (64-bit)
OS Version: Windows 7, 8, 10
URLs (if applicable) :
Other browsers tested:
  N/A

What steps will reproduce the problem?
1. Register the location of a NativeMessagingHost manifest in the 32-bit version of HKEY_LOCAL_MACHINE\SOFTWARE\Google\Chrome\NativeMessagingHosts\com.my_company.my_application
2. Attempt to use your native messaging host from your extension (it doesn't work)
3. Register the location in the 64-bit version of the same key
4. Attempt to use your native messaging host from your extension (it does work, even if it's a 32 bit executable)



What is the expected result?

According to the Chrome documentation on Native Messaging, "When Chrome looks for native messaging hosts, first the 32-bit registry is queried, then the 64-bit registry."

Registering the key in the 32-bit registry (which is all a typical MSI installer for a 32-bit application can write to) should work even with 64-bit chrome.

What happens instead of that?

Registering the key in the 32-bit registry does not have any effect on 64-bit chrome. I have no attempted it on 64-bit chrome



Please provide any additional information below. Attach a screenshot if
possible.

UserAgentString: "Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36"

The problem can be seen when using the GradeCam per-machine installer: https://downloads.gradecam.com/plugin/current/win-enterprise2

The per-user installer (which installs to HKCU) works, but when teachers at schools attempt to install for all users the installer adds the key to the 32-bit HKLM section of the registry (found in HKLM\Software\Wow6432Node\Google\Chrome\NativeMessagingHosts) and the browser does not honor the manifest file.