CrOS Tablet Window management - Split Screen part I

ash/BUILD.gn

Index: ash/BUILD.gn
diff --git a/ash/BUILD.gn b/ash/BUILD.gn
index 04c1ca663216db73bd297ad84a641462b4639db9..11e281da7c6ccdfda24f05c2f3132af79b2b8e37 100644
--- a/ash/BUILD.gn
+++ b/ash/BUILD.gn
@@ -692,6 +692,8 @@ component("ash") {
     "wm/overview/cleanup_animation_observer.cc",
     "wm/overview/cleanup_animation_observer.h",
     "wm/overview/overview_animation_type.h",
+    "wm/overview/overview_window_drag_controller.cc",
+    "wm/overview/overview_window_drag_controller.h",
     "wm/overview/scoped_overview_animation_settings.cc",
     "wm/overview/scoped_overview_animation_settings.h",
     "wm/overview/scoped_transform_overview_window.cc",
@@ -735,6 +737,8 @@ component("ash") {
     "wm/session_state_animator.h",
     "wm/session_state_animator_impl.cc",
     "wm/session_state_animator_impl.h",
+    "wm/splitview/split_view_controller.cc",
+    "wm/splitview/split_view_controller.h",
     "wm/stacking_controller.cc",
     "wm/stacking_controller.h",
     "wm/switchable_windows.cc",