Add {Lock,Unlock,Show,Hide}Cursor() to the window manager mojom.

services/ui/ws/BUILD.gn

Index: services/ui/ws/BUILD.gn
diff --git a/services/ui/ws/BUILD.gn b/services/ui/ws/BUILD.gn
index cea34fdbe84b4e00b036c69cd721a732bd45c20b..670b153e6ad05dd8e076ecb8518bc6308e18d138 100644
--- a/services/ui/ws/BUILD.gn
+++ b/services/ui/ws/BUILD.gn
@@ -23,6 +23,8 @@ static_library("lib") {
     "accessibility_manager.h",
     "cursor_location_manager.cc",
     "cursor_location_manager.h",
+    "cursor_state.cc",
+    "cursor_state.h",
     "default_access_policy.cc",
     "default_access_policy.h",
     "display.cc",
@@ -232,6 +234,7 @@ group("tests") {
 service_test("mus_ws_unittests") {
   sources = [
     "cursor_location_manager_unittest.cc",
+    "cursor_state_unittest.cc",
     "cursor_unittest.cc",
     "display_unittest.cc",
     "drag_controller_unittest.cc",