Support Multi-Process Firefox (currently in Developer Edition)

[pariser]

Firefox Developer Edition recently shipped with multi-process mode, where each tab runs in a separate process. It looks to be breaking the Rainbow extension (which is super useful - thanks!)

While running Firefox Developer Edition with multi-process mode on, Rainbow works when hovering over the browser's chrome and on certain special Firefox pages (about:preferences, etc.). It does not work on any websites.

I unchecked the "Enable multi-process Firefox Developer Edition" preference and restarted the browser; then Rainbow was working as intended. I checked the preference and restarted the browser; Rainbow was no longer working as intended.

Links:

• https://developer.mozilla.org/en-US/Add-ons/Working_with_multiprocess_Firefox
• https://wiki.mozilla.org/Electrolysis
• http://arewee10syet.com/
• https://bugzilla.mozilla.org/show_bug.cgi?id=1138113

Screenshots:

• Rainbow not working, github.com (my mouse is hovering over the blue "Issues" button)
• Rainbow working, hovering on the browser's chrome
• Rainbow working, about:preferences