Add InputEvent and EventPacket types for batched input delivery

content/common/input/event_packet.h

+// Copyright (c) 2013 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_EVENT_PACKET_H_
+#define CONTENT_COMMON_INPUT_EVENT_PACKET_H_
+
+#include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
+#include "content/common/content_export.h"
+
+namespace content {
+
+class InputEvent;
+
+// An id'ed sequence of InputEvents.
+class CONTENT_EXPORT EventPacket {
+ public:
+  typedef ScopedVector<InputEvent> InputEvents;
+
+  EventPacket();
+  ~EventPacket();
+
+  // |event| should be non-NULL and valid.

[palmer, 2013/09/03 23:12:47]

Should, or must? What happens if I pass a NULL or invalid event in?

+  void Add(scoped_ptr<InputEvent> event);
+
+  bool empty() const { return events.empty(); }
+  size_t size() const { return events.size(); }
+  InputEvents::const_iterator begin() const { return events.begin(); }

[palmer, 2013/09/03 23:12:47]

It seems like these accessors exist to hide the exact implementation (i.e., the
fact that |events| is a vector), but |events| is public. So this interface is
"partially encapsulated", if you will. I would decide to either make |events|
and |id| private (and provide accessors for |id|), or make them public and not
have these wrapper functions.

[jdduke (slow), 2013/09/04 17:53:24]

Less for hiding and more for convenience, really.  The members are public only
for automated serialization via macros, but I think stricter enforcement here is
worth the custom serialization code.

+  InputEvents::const_iterator end() const { return events.end(); }
+
+  int64 id;
+  InputEvents events;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(EventPacket);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_INPUT_EVENT_PACKET_H_