Fix memory leaks with V8 startup data.

samples/pdfium_test.cc

Index: samples/pdfium_test.cc
diff --git a/samples/pdfium_test.cc b/samples/pdfium_test.cc
index 5ee14642e4b7993f2d5de807f67f7427ca65ddfb..4f95caa60162928eb4139415e239de9d69d3c54c 100644
--- a/samples/pdfium_test.cc
+++ b/samples/pdfium_test.cc
@@ -839,6 +839,11 @@ int main(int argc, const char* argv[]) {
 #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;