mus: Let clients set the cursor of their window.

components/mus/public/cpp/lib/in_flight_change.h

Index: components/mus/public/cpp/lib/in_flight_change.h
diff --git a/components/mus/public/cpp/lib/in_flight_change.h b/components/mus/public/cpp/lib/in_flight_change.h
index 33d041789f9fd8158c10453a35c90da670a1c38d..8179cf62599204ffcbc3d9633acc256a4ef1bf46 100644
--- a/components/mus/public/cpp/lib/in_flight_change.h
+++ b/components/mus/public/cpp/lib/in_flight_change.h
@@ -15,6 +15,10 @@
 
 namespace mus {
 
+namespace mojom {
+enum Cursor : int32_t;
+}
+
 class Window;
 
 enum class ChangeType {
@@ -22,6 +26,7 @@ enum class ChangeType {
   BOUNDS,
   DELETE_WINDOW,
   NEW_WINDOW,
+  PREDEFINED_CURSOR,
   PROPERTY,
   REMOVE_TRANSIENT_WINDOW_FROM_PARENT,
   VISIBLE,
@@ -131,6 +136,21 @@ class InFlightPropertyChange : public InFlightChange {
   DISALLOW_COPY_AND_ASSIGN(InFlightPropertyChange);
 };
 
+class InFlightPredefinedCursorChange : public InFlightChange {
+ public:
+  InFlightPredefinedCursorChange(Window* window, mojom::Cursor revert_value);
+  ~InFlightPredefinedCursorChange() override;
+
+  // InFlightChange:
+  void SetRevertValueFrom(const InFlightChange& change) override;
+  void Revert() override;
+
+ private:
+  mojom::Cursor revert_cursor_;
+
+  DISALLOW_COPY_AND_ASSIGN(InFlightPredefinedCursorChange);
+};
+
 class InFlightVisibleChange : public InFlightChange {
  public:
   InFlightVisibleChange(Window* window, const bool revert_value);