Implement Main Thread RAF Aligned Input

content/common/input/web_input_event_queue.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_COMMON_INPUT_WEB_INPUT_EVENT_QUEUE_H_
 #define CONTENT_COMMON_INPUT_WEB_INPUT_EVENT_QUEUE_H_
 
 #include <deque>
 #include <memory>
 
@@ skipping 18 matching lines @@
 
       if ((*last_event_iter)->CanCoalesceWith(*event.get())) {
         (*last_event_iter)->CoalesceWith(*event.get());
         return;
       }
       break;
     }
     queue_.emplace_back(std::move(event));
   }
 
+  const std::unique_ptr<T>& front() const { return queue_.front(); }
+  const std::unique_ptr<T>& at(size_t pos) const { return queue_.at(pos); }
+
   std::unique_ptr<T> Pop() {
     std::unique_ptr<T> result;
     if (!queue_.empty()) {
       result.reset(queue_.front().release());
       queue_.pop_front();
     }
     return result;
   }
 
   bool empty() const { return queue_.empty(); }
 
   size_t size() const { return queue_.size(); }
 
  private:
   typedef std::deque<std::unique_ptr<T>> EventQueue;
   EventQueue queue_;
 
   DISALLOW_COPY_AND_ASSIGN(WebInputEventQueue);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_INPUT_WEB_INPUT_EVENT_QUEUE_H_