AU: Provide a reboot_if_needed D-Bus API.

AU: Provide a reboot_if_needed D-Bus API.

This will reboot if the current state is UPDATED_REBOOT_NEEDED.
Also add -reboot option to the update_engine_client.

BUG=4250
TEST=unit tests,gmerged on device and tried reboot requests

[adlr, 2010-07-22 23:38:49]

LGTM w/ comment

http://codereview.chromium.org/3034026/diff/2001/3006
File update_engine_client.cc (right):

http://codereview.chromium.org/3034026/diff/2001/3006#newcode190
update_engine_client.cc:190: LOG(INFO) << "Requesting a reboot...";
this is a little weird, b/c if a user passes check_for_update AND reboot, it
will check for update OR reboot, but not both.

[petkov, 2010-07-22 23:41:17]

http://codereview.chromium.org/3034026/diff/2001/3006
File update_engine_client.cc (right):

http://codereview.chromium.org/3034026/diff/2001/3006#newcode190
update_engine_client.cc:190: LOG(INFO) << "Requesting a reboot...";
On 2010/07/22 23:38:49, adlr wrote:
> this is a little weird, b/c if a user passes check_for_update AND reboot, it
> will check for update OR reboot, but not both.

What do you mean? This is inside the check for update -- so if you pass both
flags, you'll check for update first, and then reboot.

[petkov, 2010-07-23 17:17:22]

PTAL

http://codereview.chromium.org/3034026/diff/2001/3006
File update_engine_client.cc (right):

http://codereview.chromium.org/3034026/diff/2001/3006#newcode190
update_engine_client.cc:190: LOG(INFO) << "Requesting a reboot...";
On 2010/07/22 23:41:17, petkov wrote:
> On 2010/07/22 23:38:49, adlr wrote:
> > this is a little weird, b/c if a user passes check_for_update AND reboot, it
> > will check for update OR reboot, but not both.
> 
> What do you mean? This is inside the check for update -- so if you pass both
> flags, you'll check for update first, and then reboot.
> 

... which would work, if the calls weren't asynchronous...

Changed so that -reboot is ignored if combined with other options.

[adlr, 2010-07-23 19:55:49]

LGTM