Devirtualize base::BindState to save ~1% of Chrome's binary size (~1MB)

base/bind_internal.h

Index: base/bind_internal.h
diff --git a/base/bind_internal.h b/base/bind_internal.h
index 5fc14592cd3a62fff3e1a830a6f229d4a26ef821..e05321886223f8863693aba9e910408dc463696e 100644
--- a/base/bind_internal.h
+++ b/base/bind_internal.h
@@ -364,9 +364,10 @@ template <typename Runnable, typename RunType, typename BoundArgList>
 struct BindState;
 
 template <typename Runnable,
-          typename R, typename... Args,
+          typename R,
+          typename... Args,
           typename... BoundArgs>
-struct BindState<Runnable, R(Args...), TypeList<BoundArgs...>>
+struct BindState<Runnable, R(Args...), TypeList<BoundArgs...>> final
     : public BindStateBase {
  private:
   using StorageType = BindState<Runnable, R(Args...), TypeList<BoundArgs...>>;
@@ -398,14 +399,21 @@ struct BindState<Runnable, R(Args...), TypeList<BoundArgs...>>
   using UnboundRunType = MakeFunctionType<R, UnboundArgs>;
 
   BindState(const Runnable& runnable, const BoundArgs&... bound_args)
-      : runnable_(runnable), ref_(bound_args...), bound_args_(bound_args...) {}
+      : BindStateBase(&Destroy),
+        runnable_(runnable),
+        ref_(bound_args...),
+        bound_args_(bound_args...) {}
 
   RunnableType runnable_;
   MaybeScopedRefPtr<HasIsMethodTag<Runnable>::value, BoundArgs...> ref_;
   Tuple<BoundArgs...> bound_args_;
 
  private:
-  ~BindState() override {}
+  ~BindState() {}
+
+  static void Destroy(BindStateBase* self) {
+    delete static_cast<BindState*>(self);
+  }
 };
 
 }  // namespace internal