Update ui::PointerEvent to support mouse wheel and capture change events.

ui/views/mus/pointer_watcher_event_router.cc

Index: ui/views/mus/pointer_watcher_event_router.cc
diff --git a/ui/views/mus/pointer_watcher_event_router.cc b/ui/views/mus/pointer_watcher_event_router.cc
index 3696acb569d9790f9d252922d373c733633ee23d..ff24349f026871849df1b73d9cf2b79d51c053f1 100644
--- a/ui/views/mus/pointer_watcher_event_router.cc
+++ b/ui/views/mus/pointer_watcher_event_router.cc
@@ -6,6 +6,7 @@
 
 #include "services/ui/public/cpp/window.h"
 #include "services/ui/public/cpp/window_tree_client.h"
+#include "ui/display/screen.h"
 #include "ui/events/base_event_utils.h"
 #include "ui/events/event.h"
 #include "ui/views/mus/native_widget_mus.h"
@@ -85,7 +86,11 @@ bool PointerWatcherEventRouter::HasPointerWatcher() {
 void PointerWatcherEventRouter::OnWindowTreeCaptureChanged(
     ui::Window* gained_capture,
     ui::Window* lost_capture) {
-  FOR_EACH_OBSERVER(PointerWatcher, pointer_watchers_, OnMouseCaptureChanged());
+  const ui::MouseEvent mouse_event(ui::ET_MOUSE_CAPTURE_CHANGED, gfx::Point(),
+                                   gfx::Point(), ui::EventTimeForNow(), 0, 0);
+  const ui::PointerEvent event(mouse_event);
+  FOR_EACH_OBSERVER(PointerWatcher, pointer_watchers_,
+                    OnPointerEventObserved(event, gfx::Point(), nullptr));
 }
 
 void PointerWatcherEventRouter::OnDidDestroyClient(