Rename the aura_shell namespace to ash

Rename the aura_shell namespace to ash

http://crbug.com/108457
TEST=none
TBR=sky
Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=115748

[tfarina, 2011-12-24 00:48:55]

http://codereview.chromium.org/9033007/diff/1/ash/accelerators/accelerator_co...
File ash/accelerators/accelerator_controller.h (right):

http://codereview.chromium.org/9033007/diff/1/ash/accelerators/accelerator_co...
ash/accelerators/accelerator_controller.h:14: #include "ash/ash_export.h"
nit: sort, we could pass tool/sort_headers.py in these files in a follow up.

[commit-bot: I haz the power, 2011-12-24 00:49:20]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ben@chromium.org/9033007/1

[commit-bot: I haz the power, 2011-12-24 02:10:52]

Try job failure for 9033007-1 (retry) on linux_rel for steps "browser_tests,
ui_tests".
It's a second try, previously, steps "browser_tests, ui_tests" failed.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_rel&...