Set the unique_event_id when converting from TouchEvent to WebTouchEvent

content/common/input/web_input_event_traits.cc

Index: content/common/input/web_input_event_traits.cc
diff --git a/content/common/input/web_input_event_traits.cc b/content/common/input/web_input_event_traits.cc
index 6ca962b5720d9741d2b6bc4d4d251f7e9a86b9ec..edf0fe04a51c4908e30cb62302ac9bba03440d02 100644
--- a/content/common/input/web_input_event_traits.cc
+++ b/content/common/input/web_input_event_traits.cc
@@ -108,10 +108,12 @@ void ApppendTouchPointDetails(const WebTouchPoint& point, std::string* result) {
 
 void ApppendEventDetails(const WebTouchEvent& event, std::string* result) {
   StringAppendF(result,
-                "{\n Touches: %u, Cancelable: %d, CausesScrolling: %d\n[\n",
+                "{\n Touches: %u, Cancelable: %d, CausesScrolling: %d,"
+                " uniqueTouchEventId: %u\n[\n",
                 event.touchesLength,
                 event.cancelable,
-                event.causesScrollingIfUncanceled);
+                event.causesScrollingIfUncanceled,
+                static_cast<uint32_t>(event.uniqueTouchEventId));

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

I think we have some 64-bit printf-style helpers for formatting, but I don't
seem to recall where they are.

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

I found "PRIu64", is this the one you have seen before?

   for (unsigned i = 0; i < event.touchesLength; ++i)
     ApppendTouchPointDetails(event.touches[i], result);
   result->append(" ]\n}");