Move bookmarks extension api implementation to bookmarks dir

Move bookmarks extension api implementation to bookmarks dir.

We're moving all the extension api implementations out of
browser/extensions into the directory with the code they are
automating.

BUG=101244
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=107069

[Aaron Boodman, 2011-10-22 05:40:09]

This is just a pure move, no functionality change.

[akalin, 2011-10-22 06:19:28]

sync LGTM

[sky, 2011-10-24 15:05:23]

Rubber stamp LGTM

[commit-bot: I haz the power, 2011-10-24 19:02:27]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/aa@chromium.org/8374023/5001

[commit-bot: I haz the power, 2011-10-24 19:05:07]

Commit queue patch verification failed without an error message.
Something went wrong, probably a crash, a hickup or simply
the monkeys went out for diner.
Ping the relevant dude on a on-needed basis.