chromeos: Support turning displays off in extended mode.

chromeos/display/output_configurator.h

Index: chromeos/display/output_configurator.h
diff --git a/chromeos/display/output_configurator.h b/chromeos/display/output_configurator.h
index 042933143b71fcbb7c7d674e403db7f1b70a818b..894f82a9e6b4827ec3375821760ec4d44d7629c4 100644
--- a/chromeos/display/output_configurator.h
+++ b/chromeos/display/output_configurator.h
@@ -104,8 +104,13 @@ class CHROMEOS_EXPORT OutputConfigurator : public MessageLoop::Dispatcher {
   // on or off.  This requires enabling or disabling the CRTC associated with
   // the display(s) in question so that the low power state is engaged.
   // If |force_probe| is true, the displays will be configured even if
-  // |power_state| matches |power_state_|.
-  bool SetDisplayPower(DisplayPowerState power_state, bool force_probe);
+  // |power_state| matches |power_state_|. If
+  // |only_if_single_internal_display| is true, the state will not be
+  // changed if multiple displays are connected or if the display is not
+  // internal.
+  bool SetDisplayPower(DisplayPowerState power_state,
+                       bool force_probe,
+                       bool only_if_single_internal_display);

[Daniel Erat, 2013/03/27 23:15:19]

I would've preferred to let callers deal with the "only if single internal"
check, but that seems tricky due us needing to reprobe every time this is called
-- I think that improving that is a bit more than we should try to deal with for
27.

 
   // Force switching the display mode to |new_state|. Returns false if
   // it was called in a single-head or headless mode.