Return v8::Date specialization not v8::Value where possible

fxjs/fxjs_v8.cpp

 // Copyright 2014 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/include/fxjs_v8.h"
 
 #include <vector>
 
@@ skipping 740 matching lines @@
 }
 
 v8::Local<v8::Value> FXJS_NewString(v8::Isolate* pIsolate, const wchar_t* str) {
   return FXJS_WSToJSString(pIsolate, str);
 }
 
 v8::Local<v8::Value> FXJS_NewNull(v8::Isolate* pIsolate) {
   return v8::Local<v8::Value>();
 }
 
-v8::Local<v8::Value> FXJS_NewDate(v8::Isolate* pIsolate, double d) {
-  return v8::Date::New(pIsolate->GetCurrentContext(), d).ToLocalChecked();
+v8::Local<v8::Date> FXJS_NewDate(v8::Isolate* pIsolate, double d) {
+  return v8::Date::New(pIsolate->GetCurrentContext(), d)
+      .ToLocalChecked()
+      .As<v8::Date>();
 }
 
 int FXJS_ToInt32(v8::Isolate* pIsolate, v8::Local<v8::Value> pValue) {
   if (pValue.IsEmpty())
     return 0;
   v8::Local<v8::Context> context = pIsolate->GetCurrentContext();
   return pValue->ToInt32(context).ToLocalChecked()->Value();
 }
 
 bool FXJS_ToBoolean(v8::Isolate* pIsolate, v8::Local<v8::Value> pValue) {
@@ skipping 27 matching lines @@
   return CFX_WideString::FromUTF8(CFX_ByteStringC(*s, s.length()));
 }
 
 v8::Local<v8::Array> FXJS_ToArray(v8::Isolate* pIsolate,
                                   v8::Local<v8::Value> pValue) {
   if (pValue.IsEmpty())
     return v8::Local<v8::Array>();
   v8::Local<v8::Context> context = pIsolate->GetCurrentContext();
   return v8::Local<v8::Array>::Cast(pValue->ToObject(context).ToLocalChecked());
 }
-
-void FXJS_ValueCopy(v8::Local<v8::Value>& pTo, v8::Local<v8::Value> pFrom) {
-  pTo = pFrom;
-}