Use "= default' in more places.

See https://abseil.io/tips/131 for explanation.

Change-Id: I569e9b65176b072e75f39c33281e91776cf188cf
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/78911
Reviewed-by: Hui Yingst <nigi@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
diff --git a/fxjs/cfx_globaldata_unittest.cpp b/fxjs/cfx_globaldata_unittest.cpp
index 9a204e9..24c080a 100644
--- a/fxjs/cfx_globaldata_unittest.cpp
+++ b/fxjs/cfx_globaldata_unittest.cpp
@@ -14,7 +14,7 @@
 class TestDelegate : public CFX_GlobalData::Delegate {
  public:
   TestDelegate() = default;
-  ~TestDelegate() override {}
+  ~TestDelegate() override = default;
 
   bool StoreBuffer(pdfium::span<const uint8_t> buffer) override {
     last_buffer_ = std::vector<uint8_t, FxAllocAllocator<uint8_t>>(