Fix memory leaks with V8 startup data.

samples/pdfium_test.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include <list>
@@ skipping 821 matching lines @@
         }
       }
     }
     RenderPdf(filename, file_contents.get(), file_length, options, events);
   }
 
   FPDF_DestroyLibrary();
 #ifdef PDF_ENABLE_V8
   v8::V8::ShutdownPlatform();
   delete platform;
+
+#ifdef V8_USE_EXTERNAL_STARTUP_DATA
+  free(const_cast<char*>(natives.data));
+  free(const_cast<char*>(snapshot.data));
+#endif  // V8_USE_EXTERNAL_STARTUP_DATA
 #endif  // PDF_ENABLE_V8
 
   return 0;
 }