chromeos: Make OutputConfigurator save latest config.

chromeos: Make OutputConfigurator save latest config.

This updates the OutputConfigurator class to save
OutputSnapshot structs describing outputs' last-configured
states.

Planned changes that will build on this one:

1. Make OutputConfigurator ignore RRNotify events describing
   the same configuration that was just requested.

2. Add additional data to OutputSnapshot and pass snapshots
   to observers so they don't need to query the current
   state themselves.

BUG=254667, 266113
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=216536

[oshima, 2013-08-08 01:19:49]

lgtm with two cleanup requests.(can be in separate CL)

https://codereview.chromium.org/22605008/diff/3001/chromeos/display/output_co...
File chromeos/display/output_configurator.cc (right):

https://codereview.chromium.org/22605008/diff/3001/chromeos/display/output_co...
chromeos/display/output_configurator.cc:410: case STATE_HEADLESS:
do you think we can nuke STATE_HEADLESS?

https://codereview.chromium.org/22605008/diff/3001/chromeos/display/output_co...
chromeos/display/output_configurator.cc:514: return false;
let's remove default because output_state is enum.

[marcheu, 2013-08-08 15:02:31]

lgtm

[Daniel Erat, 2013-08-08 16:07:37]

https://codereview.chromium.org/22605008/diff/3001/chromeos/display/output_co...
File chromeos/display/output_configurator.cc (right):

https://codereview.chromium.org/22605008/diff/3001/chromeos/display/output_co...
chromeos/display/output_configurator.cc:410: case STATE_HEADLESS:
On 2013/08/08 01:19:49, oshima wrote:
> do you think we can nuke STATE_HEADLESS?

What's the alternate proposal? Do you think we should use STATE_SINGLE when a
Chromebox doesn't have any displays connected?

https://codereview.chromium.org/22605008/diff/3001/chromeos/display/output_co...
chromeos/display/output_configurator.cc:514: return false;
On 2013/08/08 01:19:49, oshima wrote:
> let's remove default because output_state is enum.

It was covering STATE_INVALID. I've added a separate case for this.

[commit-bot: I haz the power, 2013-08-08 16:31:24]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/derat@chromium.org/22605008/11001

[oshima, 2013-08-08 16:52:09]

https://codereview.chromium.org/22605008/diff/3001/chromeos/display/output_co...
File chromeos/display/output_configurator.cc (right):

https://codereview.chromium.org/22605008/diff/3001/chromeos/display/output_co...
chromeos/display/output_configurator.cc:410: case STATE_HEADLESS:
On 2013/08/08 16:07:37, Daniel Erat wrote:
> On 2013/08/08 01:19:49, oshima wrote:
> > do you think we can nuke STATE_HEADLESS?
> 
> What's the alternate proposal? Do you think we should use STATE_SINGLE when a
> Chromebox doesn't have any displays connected?

Exit early if there is no output and just leave the state as is.
Not sure if that's possible, or better though. Just wondering because
chrome has no headless state and just ignores such change.

[commit-bot: I haz the power, 2013-08-08 19:50:11]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/derat@chromium.org/22605008/19001

[commit-bot: I haz the power, 2013-08-09 01:53:39]

Change committed as 216536