Add id properties to PointerEvent

ui/events/events_default.cc

Index: ui/events/events_default.cc
diff --git a/ui/events/events_default.cc b/ui/events/events_default.cc
index 8182b4a7801270d2e9675aaf26c89605a00b1cfb..fac647240efaabd6a4b26dde117c7eb0f682ba3f 100644
--- a/ui/events/events_default.cc
+++ b/ui/events/events_default.cc
@@ -53,7 +53,9 @@ PointerDetails GetMousePointerDetailsFromNative(
   const ui::MouseEvent* event =
       static_cast<const ui::MouseEvent*>(native_event);
   DCHECK(event->IsMouseEvent() || event->IsScrollEvent());
-  return event->pointer_details();
+  PointerDetails pointer_detail = event->pointer_details();
+  pointer_detail.id = PointerEvent::kMousePointerId;
+  return pointer_detail;
 }
 
 KeyboardCode KeyboardCodeFromNative(const base::NativeEvent& native_event) {
@@ -91,11 +93,12 @@ void ReleaseCopiedNativeEvent(const base::NativeEvent& event) {
 void ClearTouchIdIfReleased(const base::NativeEvent& xev) {
 }
 
+// TODO(687724): Will remove all GetTouchId functions.
 int GetTouchId(const base::NativeEvent& native_event) {
   const ui::TouchEvent* event =
       static_cast<const ui::TouchEvent*>(native_event);
   DCHECK(event->IsTouchEvent());
-  return event->touch_id();
+  return event->pointer_details().id;
 }
 
 PointerDetails GetTouchPointerDetailsFromNative(