In the latest version of Chromium Version 44.0.2403.125 (64-bit), when there is a video flash object embedded on the page, and the "expand to full screen mode" icon is pressed, the video does not expand to full screen. Rather, Flash goes into a 'full screen mode', but the background is black, and the video only appears in the top left hand corner with the same small dimensions as the original embedded video. The expected behaviour is the video expands to the size of the full screen. This has been consistent with every embedded flash video I've seen. I'm running OS X Yosemite 10.10.4. I took screenshots but am unable to post due to 'low-karma'.
Pepper Flash (v. 184.108.40.206) in Chromium is the same as in Chrome.