How-To Geek explains what the heck they actually do.
Native Client: This allows developers to run C or C++ code on a web site.
Adobe Flash: This is Adobe Flash, but tweaked a bit for Google Chrome.
Chrome Remote Desktop Viewer: This is the Chrome Remote Desktop app needed to access your gear remotely.
The plug-in doesn’t do anything unless you activate it.
it’s possible for you to alwaysdisable any of these, but you’ll lose functionality as expected.
Google Chrome Includes 5 surfing app Plug-Ins, and Here’s What They Do| How-To Geek