Set the unique_event_id when converting from TouchEvent to WebTouchEvent

ui/events/gesture_detection/motion_event_generic.cc

Index: ui/events/gesture_detection/motion_event_generic.cc
diff --git a/ui/events/gesture_detection/motion_event_generic.cc b/ui/events/gesture_detection/motion_event_generic.cc
index 475e9c5bc808eb3d40f042fd5a8aff751a4858c5..a964ca84cf9215507651f5dea57dea5bf06b4ad2 100644
--- a/ui/events/gesture_detection/motion_event_generic.cc
+++ b/ui/events/gesture_detection/motion_event_generic.cc
@@ -46,7 +46,6 @@ MotionEventGeneric::MotionEventGeneric(Action action,
                                        const PointerProperties& pointer)
     : action_(action),
       event_time_(event_time),
-      id_(0),
       action_index_(0),

[jdduke (slow), 2015/04/17 20:30:01]

unique_event_id_ needs to be initialized in all of these constructors

[lanwei, 2015/04/20 19:58:59]

The MotionEventGeneric's unique_event_id is from TouchEvent, so we do not
generate it in its constructor.

[jdduke (slow), 2015/04/21 14:56:50]

I don't fully understand this comment, what do you mean it's from TouchEvent?
Even if we don't create a new ID here, don't we have to initialize the member
variable to 0?

[lanwei, 2015/04/21 21:32:45]

Sorry, I was wrong, I thought we do not pass MotionEventGeneric objects to the
CreateWebTouchEventFromMotionEvent function, so we do not care if it has a
unique_event_id value. We should initialize the unique_event_id in all the
constructors. 

       button_state_(0),
       flags_(0) {
@@ -56,7 +55,6 @@ MotionEventGeneric::MotionEventGeneric(Action action,
 MotionEventGeneric::MotionEventGeneric(const MotionEventGeneric& other)
     : action_(other.action_),
       event_time_(other.event_time_),
-      id_(other.id_),
       action_index_(other.action_index_),
       button_state_(other.button_state_),
       flags_(other.flags_),
@@ -69,8 +67,8 @@ MotionEventGeneric::MotionEventGeneric(const MotionEventGeneric& other)
 MotionEventGeneric::~MotionEventGeneric() {
 }
 
-int MotionEventGeneric::GetId() const {
-  return id_;
+uint64 MotionEventGeneric::GetUniqueEventId() const {
+  return unique_event_id_;
 }
 
 MotionEvent::Action MotionEventGeneric::GetAction() const {
@@ -219,14 +217,13 @@ void MotionEventGeneric::PushHistoricalEvent(scoped_ptr<MotionEvent> event) {
 }
 
 MotionEventGeneric::MotionEventGeneric()
-    : action_(ACTION_CANCEL), id_(0), action_index_(0), button_state_(0) {
+    : action_(ACTION_CANCEL), action_index_(0), button_state_(0) {
 }
 
 MotionEventGeneric::MotionEventGeneric(const MotionEvent& event,
                                        bool with_history)
     : action_(event.GetAction()),
       event_time_(event.GetEventTime()),
-      id_(event.GetId()),
       action_index_(
           (action_ == ACTION_POINTER_UP || action_ == ACTION_POINTER_DOWN)
               ? event.GetActionIndex()
@@ -259,7 +256,6 @@ MotionEventGeneric& MotionEventGeneric::operator=(
     const MotionEventGeneric& other) {
   action_ = other.action_;
   event_time_ = other.event_time_;
-  id_ = other.id_;
   action_index_ = other.action_index_;

[jdduke (slow), 2015/04/17 20:30:01]

Don't we need to copy the unique_event_id_?

[lanwei, 2015/04/20 19:58:59]

Done.

   button_state_ = other.button_state_;
   flags_ = other.flags_;