Collapse the API surface on WebInputEvent via accessor functions.

ui/events/blink/event_with_callback.cc

Index: ui/events/blink/event_with_callback.cc
diff --git a/ui/events/blink/event_with_callback.cc b/ui/events/blink/event_with_callback.cc
index aeec0fc7c6d5bf943ea6e193084f274a0a149e32..cf018fba8c34ef6058d52ca52f2fa42c515a56c1 100644
--- a/ui/events/blink/event_with_callback.cc
+++ b/ui/events/blink/event_with_callback.cc
@@ -40,7 +40,7 @@ void EventWithCallback::CoalesceWith(EventWithCallback* other,
 
   // New events get coalesced into older events, and the newer timestamp
   // should always be preserved.
-  const double time_stamp_seconds = other->event().timeStampSeconds;
+  const double time_stamp_seconds = other->event().timeStampSeconds();
   Coalesce(other->event(), event_.get());
   event_->setTimeStampSeconds(time_stamp_seconds);