UPDATE: The screenshots in this guide are now obsolete -- the latest versions of Chrome changed the entire "settings experience" (all settings pages) with the new and reordered "material design" style. The screenshots below are not representing the current state. But there is something good: we updated our "Plugins" extension and now you don't need this info. Just go to the adress below and install the Plugins Button:
Since Chrome™ version 57 the old internal page chrome://plugins is replaced by new address: chrome://components
The new ("components") page does not offer enable/disable functionality. If you want to enable/disable the Flash plugin: the new home for this option is in the "Settings" menu. There is also an option to change the PDF viewer.
To change Flash plugin or PDF settings:
1) Click on the "Settings" menu:
2) Scroll down to the end of the Settings page and click "Advanced...":
3) Under "Privacy", click "Content Settings" button:
4) Scroll until you find the Flash settings:
Here you can enable/disable Flash at all or on "per-site" basis.
5) Scroll to the end of the content settings and you'll find the PDF settings: