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..0138d0666ca2b043d648e313447b317d3947cd53 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) {
@@ -95,7 +97,7 @@ 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;

[sadrul, 2017/02/13 16:47:43]

Is GetTouchId() called from anywhere anymore? If not, can you remove that?
(maybe in a separate CL)

[lanwei, 2017/02/13 21:50:29]

Done.

 }
 
 PointerDetails GetTouchPointerDetailsFromNative(