Unify the three CFWL_EventType::SelectChange classes.

xfa/fwl/core/cfwl_evtselectchanged.cpp

Index: xfa/fwl/core/cfwl_evtselectchanged.cpp
diff --git a/xfa/fwl/core/cfwl_evtselectchanged.cpp b/xfa/fwl/core/cfwl_evtselectchanged.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..3eead94d6e1076950c02507f29047dfebabbf85d
--- /dev/null
+++ b/xfa/fwl/core/cfwl_evtselectchanged.cpp
@@ -0,0 +1,15 @@
+// Copyright 2016 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#include "xfa/fwl/core/cfwl_evtselectchanged.h"
+
+CFWL_EvtSelectChanged::CFWL_EvtSelectChanged() {}
+
+CFWL_EvtSelectChanged::~CFWL_EvtSelectChanged() {}
+
+CFWL_EventType CFWL_EvtSelectChanged::GetClassID() const {
+  return CFWL_EventType::SelectChanged;
+}