Keep track of coalesced events in main thread event queue

third_party/WebKit/public/platform/WebCoalescedInputEvent.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 WebCoalescedInputEvent_h
 #define WebCoalescedInputEvent_h
 
 #include "WebCommon.h"
 #include "WebInputEvent.h"
 
 #include <memory>
 #include <vector>
 
 namespace blink {
 
 struct BLINK_COMMON_EXPORT WebInputEventDeleter {
   void operator()(blink::WebInputEvent*) const;
 };
 
 using WebScopedInputEvent =
     std::unique_ptr<WebInputEvent, WebInputEventDeleter>;
 
 // This class is representing a polymorphic WebInputEvent structure with its
 // coalesced events. The event could be any events defined in WebInputEvent.h.
 class BLINK_COMMON_EXPORT WebCoalescedInputEvent {
  public:
-  WebCoalescedInputEvent(WebScopedInputEvent);
-  WebCoalescedInputEvent(const WebInputEvent&);
+  explicit WebCoalescedInputEvent(WebScopedInputEvent);
+  explicit WebCoalescedInputEvent(const WebInputEvent&);
   WebCoalescedInputEvent(const WebInputEvent&,
                          const std::vector<const WebInputEvent*>&);
 
   WebInputEvent* eventPointer();
   void addCoalescedEvent(const blink::WebInputEvent&);
   const WebInputEvent& event() const;
   size_t coalescedEventSize() const;
-  const WebInputEvent* coalescedEvent(int index) const;
+  const WebInputEvent& coalescedEvent(size_t index) const;
   std::vector<const WebInputEvent*> getCoalescedEventsPointers() const;
 
  private:
   WebScopedInputEvent m_event;
   std::vector<WebScopedInputEvent> m_coalescedEvents;
 };
 
 using WebScopedCoalescedInputEvent = std::unique_ptr<WebCoalescedInputEvent>;
 
 }  // namespace blink
 
 #endif