Revert "Switch to our own camera2"

This reverts commit 8af48c63bb7a5b13d59702245f29a3f71eda2e0b.
Track Gallery from Slim
Track ContactsProvider from CM
Track LatinIME from Slim
Track MediaProvider from Slim
Track External_Clang from Slim
Track External_Skia from Slim
Revert "Track ContactsProvider from CM"

This reverts commit 92640264455e6b295bc08aec296b06aa5e862e16.
Revert "Track External_Clang from Slim"

This reverts commit d861536a10960cd1c75e1d97e7b3b696a075a0e3.