[WIP] ScreenManager: Add an external window mode

services/ui/display/screen_manager_ozone.cc

Index: services/ui/display/screen_manager_ozone.cc
diff --git a/services/ui/display/screen_manager_ozone.cc b/services/ui/display/screen_manager_ozone.cc
index 9a8a0412b5ed77e4f2398df55d545abae2bcf714..5f3ea15ee623f1ea1d1f9e94c8ac83768be6e06f 100644
--- a/services/ui/display/screen_manager_ozone.cc
+++ b/services/ui/display/screen_manager_ozone.cc
@@ -138,7 +138,8 @@ void ScreenManagerOzone::AddInterfaces(
   registry->AddInterface<mojom::TestDisplayController>(this);
 }
 
-void ScreenManagerOzone::Init(ScreenManagerDelegate* delegate) {
+void ScreenManagerOzone::Init(ScreenManagerDelegate* delegate,
+                              WindowMode window_mode) {
   DCHECK(delegate);
   delegate_ = delegate;
 
@@ -173,12 +174,14 @@ void ScreenManagerOzone::Init(ScreenManagerDelegate* delegate) {
   display_change_observer_ = base::MakeUnique<DisplayChangeObserver>(
       &display_configurator_, display_manager_.get());
 
-  // We want display configuration to happen even off device to keep the control
-  // flow similar.
-  display_configurator_.set_configure_display(true);
-  display_configurator_.AddObserver(display_change_observer_.get());
-  display_configurator_.set_state_controller(display_change_observer_.get());
-  display_configurator_.set_mirroring_controller(display_manager_.get());
+  if (window_mode == WINDOW_MODE_INTERNAL) {
+    // We want display configuration to happen even off device to keep the
+    // control flow similar.
+    display_configurator_.set_configure_display(true);
+    display_configurator_.AddObserver(display_change_observer_.get());
+    display_configurator_.set_state_controller(display_change_observer_.get());
+    display_configurator_.set_mirroring_controller(display_manager_.get());
+  }
 
   // Perform initial configuration.
   display_configurator_.Init(std::move(native_display_delegate_), false);