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

fpdfsdk/javascript/JS_Value.h

 // 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
 
 #ifndef FPDFSDK_JAVASCRIPT_JS_VALUE_H_
 #define FPDFSDK_JAVASCRIPT_JS_VALUE_H_
 
 #include <vector>
@@ skipping 141 matching lines @@
   CJS_Date(CJS_Runtime* pRuntime, double dMsec_time);
   CJS_Date(CJS_Runtime* pRuntime,
            int year,
            int mon,
            int day,
            int hour,
            int min,
            int sec);
   virtual ~CJS_Date();
 
-  void Attach(v8::Local<v8::Value> pDate);
+  void Attach(v8::Local<v8::Date> pDate);
   bool IsValidDate() const;
 
   int GetYear() const;
   void SetYear(int iYear);
 
   int GetMonth() const;
   void SetMonth(int iMonth);
 
   int GetDay() const;
   void SetDay(int iDay);
 
   int GetHours() const;
   void SetHours(int iHours);
 
   int GetMinutes() const;
   void SetMinutes(int minutes);
 
   int GetSeconds() const;
   void SetSeconds(int seconds);
 
   CJS_Runtime* GetJSRuntime() const { return m_pJSRuntime; }
   v8::Local<v8::Value> ToV8Value() const { return m_pDate; }
   double ToDouble() const;
   CFX_WideString ToString() const;
 
  protected:
-  v8::Local<v8::Value> m_pDate;
+  v8::Local<v8::Date> m_pDate;
   CJS_Runtime* const m_pJSRuntime;
 };
 
 double JS_GetDateTime();
 int JS_GetYearFromTime(double dt);
 int JS_GetMonthFromTime(double dt);
 int JS_GetDayFromTime(double dt);
 int JS_GetHourFromTime(double dt);
 int JS_GetMinFromTime(double dt);
 int JS_GetSecFromTime(double dt);
@@ skipping 10 matching lines @@
 // names as wchar_t string literals corresponding to each positional argument.
 // The result will always contain |nKeywords| value, with unspecified ones
 // being set to type VT_unknown.
 std::vector<CJS_Value> JS_ExpandKeywordParams(
     CJS_Runtime* pRuntime,
     const std::vector<CJS_Value>& originals,
     size_t nKeywords,
     ...);
 
 #endif  // FPDFSDK_JAVASCRIPT_JS_VALUE_H_