Remove last traces of chameleon
Remove last traces of chameleon

The Chrome extension build still required chameleon, a dependency
removed by 81ce4b1.

This commit removes the last traces of chameleon (from the extension
builder and the views file) and thus fixes the Chrome build for new
checkouts.

hypothesis/browser-extension,hypothesis/browser-extension,hypothesis/browser-extension,project-star/browser-extension,project-star/browser-extension,project-star/browser-extension,hypothesis/browser-extension