Set the unique_event_id when converting from TouchEvent to WebTouchEvent

content/common/input/synthetic_web_input_event_builders.cc

Index: content/common/input/synthetic_web_input_event_builders.cc
diff --git a/content/common/input/synthetic_web_input_event_builders.cc b/content/common/input/synthetic_web_input_event_builders.cc
index 36fc28f21b920bc173f6b783c7565607b171c126..5373a4b5b1ea433242634f92ddd3fe5719fc3e2a 100644
--- a/content/common/input/synthetic_web_input_event_builders.cc
+++ b/content/common/input/synthetic_web_input_event_builders.cc
@@ -10,6 +10,20 @@
 
 namespace content {
 
+namespace {
+
+uint64 get_next_event_id() {

[tdresser, 2015/04/08 12:24:26]

Can we factor this method out into a helper somewhere? Perhaps something in the
events_base target would work?

[lanwei, 2015/04/09 04:14:28]

Done.

+  // Set the first unique_id_ to 1 because we set id to 0 for other types
+  // of events.
+  static uint64 id = 1;
+  if (id==0)
+    id++;
+  DCHECK_NE(id, 0UL);
+  return id++;
+}
+
+} // namespace
+
 using blink::WebInputEvent;
 using blink::WebKeyboardEvent;
 using blink::WebGestureEvent;
@@ -150,6 +164,7 @@ WebGestureEvent SyntheticWebGestureEventBuilder::BuildFling(
 }
 
 SyntheticWebTouchEvent::SyntheticWebTouchEvent() : WebTouchEvent() {
+  uniqueTouchEventId = get_next_event_id();
   SetTimestamp(base::TimeTicks::Now() - base::TimeTicks());
 }