mus: Add watcher for all touch events.

services/ui/ws/test_change_tracker.h

Index: services/ui/ws/test_change_tracker.h
diff --git a/services/ui/ws/test_change_tracker.h b/services/ui/ws/test_change_tracker.h
index 6fa86118a88ae95d71d3ad11304bfe4c6b2f4b07..b4fcb66c09736de3afd8873d63d0abf5c846d0f0 100644
--- a/services/ui/ws/test_change_tracker.h
+++ b/services/ui/ws/test_change_tracker.h
@@ -68,6 +68,7 @@ struct Change {
   Change();
   Change(const Change& other);
   ~Change();
+  Change& operator=(Change other);
 
   ChangeType type;
   ClientSpecificId client_id;
@@ -78,7 +79,7 @@ struct Change {
   gfx::Rect bounds;
   gfx::Rect bounds2;
   int32_t event_action;
-  uint32_t event_observer_id;
+  mojo::Array<uint32_t> event_observer_ids;
   mojo::String embed_url;
   mojom::OrderDirection direction;
   bool bool_value;
@@ -157,8 +158,9 @@ class TestChangeTracker {
   void OnWindowParentDrawnStateChanged(Id window_id, bool drawn);
   void OnWindowInputEvent(Id window_id,
                           const ui::Event& event,
-                          uint32_t event_observer_id);
-  void OnEventObserved(const ui::Event& event, uint32_t event_observer_id);
+                          mojo::Array<uint32_t> event_observer_id);
+  void OnEventObserved(const ui::Event& event,
+                       mojo::Array<uint32_t> event_observer_id);
   void OnWindowSharedPropertyChanged(Id window_id,
                                      mojo::String name,
                                      mojo::Array<uint8_t> data);