Teach main thread event queue about closures.

content/common/input/web_input_event_queue.h

Index: content/common/input/web_input_event_queue.h
diff --git a/content/common/input/web_input_event_queue.h b/content/common/input/web_input_event_queue.h
index 59a4d9a9c42241cf02b3f843c97e306fe197e900..6e642d338c299683e5210e63da85b4881e2969a8 100644
--- a/content/common/input/web_input_event_queue.h
+++ b/content/common/input/web_input_event_queue.h
@@ -23,7 +23,7 @@ class WebInputEventQueue {
   void Queue(std::unique_ptr<T> event) {
     for (auto last_event_iter = queue_.rbegin();
          last_event_iter != queue_.rend(); ++last_event_iter) {
-      if (!(*last_event_iter)->event().isSameEventClass(event->event())) {
+      if (!(*last_event_iter)->IsSameEventClass(*event.get())) {
         continue;
       }
 
@@ -48,6 +48,11 @@ class WebInputEventQueue {
     return result;
   }
 
+  void emplace_front(std::unique_ptr<T> event) {
+    queue_.emplace_front(std::move(event));
+  }
+  void swap(std::deque<std::unique_ptr<T>>* queue) { queue_.swap(*queue); }
+
   bool empty() const { return queue_.empty(); }
 
   size_t size() const { return queue_.size(); }