Tab dragging as implemented as a mus API.

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 bf77fc6e6b10a00d2bbb2aa8f47eac636561b908..897379d6f768d00419b7e6f50c1cf8d5587ebd6f 100644
--- a/components/mus/public/cpp/lib/in_flight_change.h
+++ b/components/mus/public/cpp/lib/in_flight_change.h
@@ -30,6 +30,7 @@ enum class ChangeType {
   ADD_CHILD,
   ADD_TRANSIENT_WINDOW,
   BOUNDS,
+  MOVE_LOOP,

[sky, 2016/06/22 23:47:56]

nit: keep sorted.

   CAPTURE,
   DELETE_WINDOW,
   FOCUS,
@@ -143,6 +144,20 @@ class InFlightBoundsChange : public InFlightChange {
   DISALLOW_COPY_AND_ASSIGN(InFlightBoundsChange);
 };
 
+class InFlightMoveLoopChange : public InFlightChange {
+ public:
+  InFlightMoveLoopChange(Window* window, const gfx::Rect& revert_bounds);
+
+  // InFlightChange:
+  void SetRevertValueFrom(const InFlightChange& change) override;
+  void Revert() override;
+
+ private:
+  gfx::Rect revert_bounds_;
+
+  DISALLOW_COPY_AND_ASSIGN(InFlightMoveLoopChange);
+};
+
 // Inflight change that crashes on failure. This is useful for changes that are
 // expected to always complete.
 class CrashInFlightChange : public InFlightChange {