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 fea3fa9d93597717f104957f5e5496e895837962..6e275a9ef100c1e19830ffdecd090cff68fe4c0a 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",
@@ -1277,6 +1281,7 @@ source_set("common_unittests") {
     "wm/screen_dimmer_unittest.cc",
     "wm/screen_pinning_controller_unittest.cc",
     "wm/session_state_animator_impl_unittest.cc",
+    "wm/splitview/split_view_controller_unittest.cc",
     "wm/stacking_controller_unittest.cc",
     "wm/system_modal_container_layout_manager_unittest.cc",
     "wm/toplevel_window_event_handler_unittest.cc",