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 7f0422635218e2eaafb94d2933d94a6b1acd069f..bdfa3cc698fa4e2b4e41dba4cc553fc1ffb1b0e7 100644
--- a/ash/BUILD.gn
+++ b/ash/BUILD.gn
@@ -696,6 +696,8 @@ 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",
@@ -739,6 +741,8 @@ 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",