Content scripts are not injecting into some empty iframes

[Eloston]

The content scripts are not injecting into some empty iframes. This may be due to the current injection method since the content scripts are only injected when the onCommitted webNavigation event fires for http, https, and file protocols. Thus, this may be fixed with the switch back to manifest content scripts in #23.

An example of this is the Vidible media player when set to use iframes.
This is an example of the Vidible player autoplaying without the extension detecting any media: http://www.codingforums.com/javascript-programming/17254-javascript-documentation-references.html
This is relevant documentation on Vidible: https://vidible.atlassian.net/wiki/display/SUP/Player+Tag+API#PlayerTagAPI-Tags

[Eloston]

User Add Iran on the Chrome Web Store reported another website that has the same symptoms as this bug: http://www.chip.de/video/Die-besten-Weihnachts-Gadgets-Video_59235988.html

[Eloston]

User Mai Ling on the Chrome Web Store reported http://ro.yahoo.com, which exhibits the same bug. The problematic iframe has id html5_container, and the video has id video. The iframe and video appears near the top of the page.