chromeos: Turn off displays on suspend

ui/display/chromeos/update_display_configuration_task.cc

Index: ui/display/chromeos/update_display_configuration_task.cc
diff --git a/ui/display/chromeos/update_display_configuration_task.cc b/ui/display/chromeos/update_display_configuration_task.cc
index 5fa7ac7f9fb303d72afa24fc5ab02ff590c4203d..d734a8a6f69b6e86b3dd86cdaf7a2a8f2c4bbf70 100644
--- a/ui/display/chromeos/update_display_configuration_task.cc
+++ b/ui/display/chromeos/update_display_configuration_task.cc
@@ -20,6 +20,7 @@ UpdateDisplayConfigurationTask::UpdateDisplayConfigurationTask(
     int power_flags,
     uint32_t background_color_argb,
     bool force_configure,
+    bool configure_cached_displays,
     const ResponseCallback& callback)
     : delegate_(delegate),
       layout_manager_(layout_manager),
@@ -28,6 +29,7 @@ UpdateDisplayConfigurationTask::UpdateDisplayConfigurationTask(
       power_flags_(power_flags),
       background_color_argb_(background_color_argb),
       force_configure_(force_configure),
+      configure_cached_displays_(configure_cached_displays),
       callback_(callback),
       force_dpms_(false),
       weak_ptr_factory_(this) {
@@ -38,12 +40,42 @@ UpdateDisplayConfigurationTask::~UpdateDisplayConfigurationTask() {
   delegate_->UngrabServer();
 }
 
+void DoNothing(ConfigureDisplaysTask::Status status) {
+}
+
 void UpdateDisplayConfigurationTask::Run() {
+  // In the default case where the displays haven't changed, try to configure
+  // without probing the display devices to speed things up.
+  if (configure_cached_displays_)
+    delegate_->GetCachedDisplays(
+        base::Bind(&UpdateDisplayConfigurationTask::OnCachedDisplaysRetrieved,
+                  weak_ptr_factory_.GetWeakPtr()));
+
   delegate_->GetDisplays(
       base::Bind(&UpdateDisplayConfigurationTask::OnDisplaysUpdated,
                  weak_ptr_factory_.GetWeakPtr()));
 }
 
+void UpdateDisplayConfigurationTask::OnCachedDisplaysRetrieved(
+    const std::vector<DisplaySnapshot*>& displays) {
+  cached_displays_ = displays;
+
+  if (cached_displays_.size() > 1 && background_color_argb_)
+    delegate_->SetBackgroundColor(background_color_argb_);
+
+  // If the user hasn't requested a display state, update it using the requested
+  // power state.
+  if (new_display_state_ == MULTIPLE_DISPLAY_STATE_INVALID)
+    new_display_state_ = ChooseDisplayState();
+
+  // If there has been any change in the requested power state and the displays
+  // aren't being turned off force a change in DPMS state.
+  force_dpms_ = ShouldForceDpms() && ShouldConfigure();
+
+  if (ShouldConfigure())
+    EnterState(base::Bind(&DoNothing));
+}
+
 void UpdateDisplayConfigurationTask::OnDisplaysUpdated(
     const std::vector<DisplaySnapshot*>& displays) {
   cached_displays_ = displays;