Tab dragging as implemented as a mus API.

components/mus/public/cpp/lib/window.cc

Index: components/mus/public/cpp/lib/window.cc
diff --git a/components/mus/public/cpp/lib/window.cc b/components/mus/public/cpp/lib/window.cc
index 83785c4544e148ee9d2f05e231b38c4c7e35a2c8..5d48d1d1fb00c85043a6e4074c03da7aaf38d1dc 100644
--- a/components/mus/public/cpp/lib/window.cc
+++ b/components/mus/public/cpp/lib/window.cc
@@ -465,6 +465,16 @@ void Window::RequestClose() {
     client_->RequestClose(this);
 }
 
+void Window::PerformWindowMove(::mus::mojom::MoveLoopSource source,
+                               const gfx::Point& cursor_location,
+                               const base::Callback<void(bool)>& callback) {
+  client_->PerformWindowMove(this, source, cursor_location, callback);
+}
+
+void Window::CancelWindowMove() {
+  client_->CancelWindowMove(this);
+}
+
 std::string Window::GetName() const {
   if (HasSharedProperty(mojom::WindowManager::kName_Property))
     return GetSharedProperty<std::string>(mojom::WindowManager::kName_Property);