Date: September 1, 2015

Source: Google announcement (ref: http://goo.gl/v5KQGy)
Due to the prevalence of ads and sometimes viruses / malware in Adobe Flash animations on websites, Google will start automatically disabling some Flash content on websites for Chromebooks and in the Google Chrome web browser for computers. This change will take effect September 1.
This may impact some educational websites that use Flash animations, for example. You can still choose whether to play Flash content by changing a setting in Chrome:
1. Open Chrome Preferences / Settings
2. Scroll to the bottom and click Show Advanced Settings
3. Privacy section
4. Content Settings
5. Plugins section
6. Select “Let me choose when to run plugin content”