mus: Introduce high-contrast mode in mus.

services/ui/ws/window_server.cc

Index: services/ui/ws/window_server.cc
diff --git a/services/ui/ws/window_server.cc b/services/ui/ws/window_server.cc
index 15108818cb839b6e1daa8717e7dae6adbd21a6e0..c2d7910e65ccd2e059060cd812eacfd3b39c0861 100644
--- a/services/ui/ws/window_server.cc
+++ b/services/ui/ws/window_server.cc
@@ -282,6 +282,16 @@ ServerWindow* WindowServer::GetFocusedWindow() {
   return nullptr;
 }
 
+void WindowServer::SetHighContrastMode(bool enabled) {
+  if (is_in_high_contrast_mode_ == enabled)
+    return;
+  is_in_high_contrast_mode_ = enabled;
+  for (Display* display : display_manager_->displays()) {
+    display->SchedulePaint(display->root_window(),
+                           gfx::Rect(display->root_window()->bounds().size()));
+  }
+}
+
 uint32_t WindowServer::GenerateWindowManagerChangeId(
     WindowTree* source,
     uint32_t client_change_id) {