In Chrome, click the three dots in the upper right of the window and then click Settings
In Settings, scroll to the bottom and click on Advanced
In Advanced, scroll down and click on the arrow next to Site Settings
In Site Settings, click on the arrow next to Flash (Block sites from running Flash)
Under Flash, click the slider next to "Block sites from running Flash (recommended)"
The slider will turn blue and will change the line to say "Ask first". You are finished :)