Fix JS_GetArrayElement to not return an empty handle on success

fpdfsdk/src/jsapi/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 "../../../core/include/fxcrt/fx_basic.h"
 #include "../../../core/include/fxcrt/fx_ext.h"
 #include "../../include/jsapi/fxjs_v8.h"
 #include "../../include/fsdk_define.h"
@@ skipping 725 matching lines @@
     return 0;
   return 1;
 }
 
 v8::Local<v8::Value> JS_GetArrayElement(IJS_Runtime* pJSRuntime,
                                         v8::Local<v8::Array> pArray,
                                         unsigned index) {
   if (pArray.IsEmpty())
     return v8::Local<v8::Value>();
   v8::Local<v8::Value> val;
-  if (pArray->Get(pJSRuntime->GetCurrentContext(), index).ToLocal(&val))
+  if (!pArray->Get(pJSRuntime->GetCurrentContext(), index).ToLocal(&val))
     return v8::Local<v8::Value>();
   return val;
 }
 
 unsigned JS_GetArrayLength(v8::Local<v8::Array> pArray) {
   if (pArray.IsEmpty())
     return 0;
   return pArray->Length();
 }
 
@@ skipping 392 matching lines @@
 
 bool JS_PortIsNan(double d) {
   return d != d;
 }
 
 double JS_LocalTime(double d) {
   return JS_GetDateTime() + _getDaylightSavingTA(d);
 }
 
 // JavaScript time implement End.