dbus: Add SoftwareScreenDimmingRequested signal.

This adds a constant containing the name of a signal that
powerd will emit on desktop machines to request that Chrome
change the screen dimming state.  It also adds several
values that will be included as arguments.

BUG=chromium:125176,chromium-os:27501,chromium-os:28663
TEST=none

Change-Id: I4ccf67600ddeee5d307e330d0ab31d3c10d67d9e
1 file changed
tree: 7a98aacff46e16b40371815e8dc3d6e8bcb35486
  1. dbus/
  2. window_manager/
  3. README