Refcount touch tracking ids to prevent freeing them too early.

ui/events/cocoa/events_mac.mm

Index: ui/events/cocoa/events_mac.mm
diff --git a/ui/events/cocoa/events_mac.mm b/ui/events/cocoa/events_mac.mm
index 7675eb6af0589a3065a18da0e405766b17d5e678..0e6b32dad8017c9125c88f4f6625fc92f5330d83 100644
--- a/ui/events/cocoa/events_mac.mm
+++ b/ui/events/cocoa/events_mac.mm
@@ -148,6 +148,10 @@ void ReleaseCopiedNativeEvent(const base::NativeEvent& event) {
   [event release];
 }
 
+void IncrementTouchIdRefCount(const base::NativeEvent& native_event) {
+  NOTIMPLEMENTED();
+}
+
 void ClearTouchIdIfReleased(const base::NativeEvent& native_event) {
   NOTIMPLEMENTED();
 }