Move DisplayList to display; add ScreenBase.

ui/display/BUILD.gn

Index: ui/display/BUILD.gn
diff --git a/ui/display/BUILD.gn b/ui/display/BUILD.gn
index f66919e0d9356b868c393305306e71f00ab06dcb..3b1cdc5211e8a05bab00cd9996cd15a499506864 100644
--- a/ui/display/BUILD.gn
+++ b/ui/display/BUILD.gn
@@ -40,6 +40,8 @@ component("display") {
     "display_export.h",
     "display_finder.cc",
     "display_finder.h",
+    "display_list.cc",
+    "display_list.h",
     "display_observer.cc",
     "display_observer.h",
     "display_switches.cc",
@@ -59,6 +61,8 @@ component("display") {
     "screen.cc",
     "screen.h",
     "screen_aura.cc",
+    "screen_base.cc",
+    "screen_base.h",
     "win/display_info.cc",
     "win/display_info.h",
     "win/dpi.cc",
@@ -187,6 +191,7 @@ test("display_unittests") {
     "chromeos/x11/display_util_x11_unittest.cc",
     "chromeos/x11/native_display_event_dispatcher_x11_unittest.cc",
     "display_change_notifier_unittest.cc",
+    "display_list_unittest.cc",
     "display_unittest.cc",
     "manager/display_layout_builder_unittest.cc",
     "manager/display_layout_unittest.cc",