npviewer.bin isn't part of Chrome - it's part of a compatibility wrapper called nspluginwrapper that makes it possible to use the 32-bit Flash plugin (and other 32-bit plugins as well) in a 64-bit browser. To 64-bit Chrome, nspluginwrapper "looks like" a 64-bit Flash plugin. But so does a real 64-bit Flash plugin, which is preferable, so I'd guess that you recently got such a plugin and thus Chrome is no longer using the nspluginwrapper version. Have you got a chrome --type=plugin process? It's been there the whole time, but with nspluginwrapper, it's just a proxy for the real plugin that runs in the npviewer.bin process. For a native 64-bit plugin, the plugin itself runs there.