Teach main thread event queue about closures.

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>
-
-namespace content {
-
-// WebInputEventQueue is a coalescing queue. It will examine
-// the current events in the queue and will attempt to coalesce with
-// the last event of the same class type.
-template <typename T>
-class WebInputEventQueue {
- public:
-  WebInputEventQueue() {}
-
-  // Adds an event to the queue. The event may be coalesced with previously
-  // queued events.
-  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())) {
-        continue;
-      }
-
-      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_