Replace CFXJSE_HostObject::type_ with polymorphic conversion methods

More foolproof technique, and saves one word in every instance at a
cost of two pointers in every subclass vtable.

Change-Id: Ied4f91d4d203b5e6d83abe751159eb7e55489bb5
Reviewed-on: https://pdfium-review.googlesource.com/38530
Commit-Queue: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/fxjs/fxjse.cpp b/fxjs/fxjse.cpp
new file mode 100644
index 0000000000..68adaa5dd3
--- /dev/null
+++ b/fxjs/fxjse.cpp
@@ -0,0 +1,19 @@
+// Copyright 2018 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 "fxjs/fxjse.h"
+
+CFXJSE_HostObject::CFXJSE_HostObject() = default;
+
+CFXJSE_HostObject::~CFXJSE_HostObject() = default;
+
+CFXJSE_FormCalcContext* CFXJSE_HostObject::AsFormCalcContext() {
+  return nullptr;
+}
+
+CXFA_Object* CFXJSE_HostObject::AsCXFAObject() {
+  return nullptr;
+}