Detect and fix overlapping displays

ash/display/display_configuration_controller.cc

Index: ash/display/display_configuration_controller.cc
diff --git a/ash/display/display_configuration_controller.cc b/ash/display/display_configuration_controller.cc
index 7f9302ab4ce76f7707319044b54bd668b909298e..f654b43f5bb928bf36d11c85fd8a9f2955cde1bc 100644
--- a/ash/display/display_configuration_controller.cc
+++ b/ash/display/display_configuration_controller.cc
@@ -160,7 +160,6 @@ bool DisplayConfigurationController::IsLimited() {
 
 void DisplayConfigurationController::SetDisplayLayoutImpl(
     std::unique_ptr<display::DisplayLayout> layout) {
-  // TODO(oshima/stevenjb): Add support for 3+ displays.
   display_manager_->SetLayoutForCurrentDisplays(std::move(layout));
   if (display_animator_)
     display_animator_->StartFadeInAnimation();