Set the unique_event_id when converting from TouchEvent to WebTouchEvent

ui/events/event.cc

Index: ui/events/event.cc
diff --git a/ui/events/event.cc b/ui/events/event.cc
index 5e7d8c86377a4d6a7c5546dcde02b6a76e6c71d4..c5ccb8d25ff262dfc63a8a6889aa1cf6bd191938 100644
--- a/ui/events/event.cc
+++ b/ui/events/event.cc
@@ -111,7 +111,9 @@ bool X11EventHasNonStandardState(const base::NativeEvent& event) {
 }
 
 unsigned long long get_next_touch_event_id() {
-  static unsigned long long id = 0;
+  // Set the first touch_event_id to 1 because we set id to 0 for other types
+  // of events.
+  static unsigned long long id = 1;
   return id++;

[tdresser, 2015/03/16 12:24:12]

We should check if id has wrapped around, and set it back to 1 if it has.

We should also add a check somewhere (possibly on the renderer side) to ensure
that touch events never have a unique id of 0.

If we are using uint32, we should change this method to return a uint32.

[lanwei, 2015/03/16 19:06:07]

Done.

 }
 
@@ -527,7 +529,7 @@ void MouseWheelEvent::UpdateForRootTransform(
 TouchEvent::TouchEvent(const base::NativeEvent& native_event)
     : LocatedEvent(native_event),
       touch_id_(GetTouchId(native_event)),
-      unique_event_id_(get_next_touch_event_id()),
+      unique_touch_event_id_(get_next_touch_event_id()),
       radius_x_(GetTouchRadiusX(native_event)),
       radius_y_(GetTouchRadiusY(native_event)),
       rotation_angle_(GetTouchAngle(native_event)),
@@ -550,7 +552,7 @@ TouchEvent::TouchEvent(EventType type,
                        base::TimeDelta time_stamp)
     : LocatedEvent(type, location, location, time_stamp, 0),
       touch_id_(touch_id),
-      unique_event_id_(get_next_touch_event_id()),
+      unique_touch_event_id_(get_next_touch_event_id()),
       radius_x_(0.0f),
       radius_y_(0.0f),
       rotation_angle_(0.0f),
@@ -571,7 +573,7 @@ TouchEvent::TouchEvent(EventType type,
                        float force)
     : LocatedEvent(type, location, location, time_stamp, flags),
       touch_id_(touch_id),
-      unique_event_id_(get_next_touch_event_id()),
+      unique_touch_event_id_(get_next_touch_event_id()),
       radius_x_(radius_x),
       radius_y_(radius_y),
       rotation_angle_(angle),