Cannot load Flash in Extensions on Chrome v21 with PepperFlash

[Bjorn Stromberg]

My extension uses SoundManager2 to play audio using an embedded flash object. After having my browser updated to v21 on 7/31 I noticed that I couldn't play audio anymore.

I use http://www.macromedia.com/support/documentation/en/flashplayer/help/settings_manager04.html to whitelist my chrome-extension url which allows me to load the flash object and communicate with it through javascript.

Going to that page with PepperFlash enabled shows one set of settings, while going there with the standard NPAPI Flash version shows the settings I expected to see. I re-whitelisted my extension in the PepperFlash settings, but it still won't load. The only way I can get the flash to load successfully in my extension is to disable PepperFlash.

I've submitted a bug here: https://code.google.com/p/chromium/issues/detail?id=140584

Any ideas why PepperFlash and NPAPI behave differently in extensions?