Tab dragging as implemented as a mus API.

components/mus/demo/mus_demo.cc

Index: components/mus/demo/mus_demo.cc
diff --git a/components/mus/demo/mus_demo.cc b/components/mus/demo/mus_demo.cc
index 017e36c14b7982ee966df12a82b42e58f5d52eb1..6065135c11ff1e1c4cd4decbcc4b84713d09bb1d 100644
--- a/components/mus/demo/mus_demo.cc
+++ b/components/mus/demo/mus_demo.cc
@@ -128,6 +128,14 @@ void MusDemo::OnAccelerator(uint32_t id, const ui::Event& event) {
   // Don't care
 }
 
+void MusDemo::OnWmPerformMoveLoop(uint32_t change_id,
+                                  uint32_t window_id,
+                                  const gfx::Point& cursor_location) {
+  // Don't care
+}
+
+void MusDemo::OnWmCancelMoveLoop(uint32_t window_id) {}
+
 void MusDemo::AllocBitmap() {
   const gfx::Rect bounds = window_->GetBoundsInRoot();