mus: Add PointerWatcher for passively observing mouse and touch events

ash/shell/shell_delegate_impl.cc

Index: ash/shell/shell_delegate_impl.cc
diff --git a/ash/shell/shell_delegate_impl.cc b/ash/shell/shell_delegate_impl.cc
index d1e6800093a4b07d92a22050ee8c3f7c99bdc6a2..4fece22e257ed6a11ac9e55291e73a5587aa94fa 100644
--- a/ash/shell/shell_delegate_impl.cc
+++ b/ash/shell/shell_delegate_impl.cc
@@ -12,6 +12,7 @@
 #include "ash/gpu_support_stub.h"
 #include "ash/media_delegate.h"
 #include "ash/new_window_delegate.h"
+#include "ash/pointer_watcher_delegate_aura.h"
 #include "ash/session/session_state_delegate.h"
 #include "ash/shell/context_menu.h"
 #include "ash/shell/example_factory.h"
@@ -253,6 +254,11 @@ ash::MediaDelegate* ShellDelegateImpl::CreateMediaDelegate() {
   return new MediaDelegateImpl;
 }
 
+std::unique_ptr<ash::PointerWatcherDelegate>
+ShellDelegateImpl::CreatePointerWatcherDelegate() {
+  return base::WrapUnique(new PointerWatcherDelegateAura);
+}
+
 ui::MenuModel* ShellDelegateImpl::CreateContextMenu(
     ash::Shelf* shelf,
     const ash::ShelfItem* item) {