Revert 17297 and 17298 for the moment.

Revert 17297 and 17298 for the moment.
Remember that trunk must work at all times!
1) Functionality is broken: sidebar/toolbox access keys no longer work
2) Localization changes are incomplete
3) Offhand it isn't clear how to disable default accesskeys; empty message page will show through the default
4) There may be other problems, and a large change to this should have some high-profile announcement of the results and implications first
If it's not going to be all ready at once, recommend putting this in a temporary work branch.