Fabric: Making Sealable debug-only thing

Summary:
@public
Now, Sealable is already error-preventing-only mechanism, no business logic relies on that.
So, it makes sense to make it debug-only to illuminate possible performance impact.

Reviewed By: mdvacca

Differential Revision: D8923597

fbshipit-source-id: 80aa9097c4b719e91de73ac59f38d3a4751f0b06

ReactCommon/fabric/core/primitives/Sealable.cpp

@@ -24,6 +24,8 @@ namespace react {
  * http://en.cppreference.com/w/cpp/language/rule_of_three
  */
 
+#ifndef NDEBUG
+
 Sealable::Sealable(): sealed_(false) {}
 
 Sealable::Sealable(const Sealable &other): sealed_(false) {};
@@ -40,7 +42,7 @@ Sealable &Sealable::operator=(const Sealable &other) {
 Sealable &Sealable::operator=(Sealable &&other) noexcept {
   ensureUnsealed();
   return *this;
-};
+}
 
 void Sealable::seal() const {
   sealed_ = true;
@@ -56,5 +58,7 @@ void Sealable::ensureUnsealed() const {
   }
 }
 
+#endif
+
 } // namespace react
 } // namespace facebook

ReactCommon/fabric/core/primitives/Sealable.h

@@ -40,6 +40,18 @@ namespace react {
  *   3. Call `seal()` at some point from which any modifications
  *      must be prevented.
  */
+
+#ifdef NDEBUG
+
+class Sealable {
+public:
+  inline void seal() const {}
+  inline bool getSealed() const { return true; }
+  inline void ensureUnsealed() const {}
+};
+
+#else
+
 class Sealable {
 public:
   Sealable();
@@ -70,5 +82,7 @@ private:
   mutable std::atomic<bool> sealed_ {false};
 };
 
+#endif
+
 } // namespace react
 } // namespace facebook