Fullscreen exit bubble is actually used to control both mouse lock and fullscreen. Addition of keyboard lock would make it the third behavior requiring some clean-up. This is part 1 of the refactor and contains just renames.

Also the difference from the original CL is that I have reverted rename of fullscreen_controller in lieu of doing it when I actually move the functionality and using exclusive_access_* instead of lock_exit.

BUG=166928

Review URL: https://codereview.chromium.org/789403002

Cr-Commit-Position: refs/heads/master@{#308231}