Warn whenever CxxNativeModules are used

Summary:
After this diff, when ReactFeatureFlags.warnOnLegacyNativeModuleSystemUse is enabled, the legacy NativeModule infra will log soft exceptions whenever legacy NativeModules are accessed/used.

Changelog: [Internal]

Reviewed By: p-sun

Differential Revision: D30272695

fbshipit-source-id: 7111402c1d8b883a600dcb4559e9ff1d56447070

ReactCommon/cxxreact/CxxNativeModule.cpp

@@ -54,6 +54,12 @@ CxxModule::Callback convertCallback(
 
 } // namespace
 
+WarnOnUsageLogger CxxNativeModule::warnOnUsageLogger_ = nullptr;
+
+void CxxNativeModule::setWarnOnUsageLogger(WarnOnUsageLogger logger) {
+  warnOnUsageLogger_ = logger;
+}
+
 std::string CxxNativeModule::getName() {
   return name_;
 }
@@ -87,6 +93,12 @@ folly::dynamic CxxNativeModule::getConstants() {
     return nullptr;
   }
 
+  if (warnOnUsageLogger_) {
+    warnOnUsageLogger_(
+        "Calling getConstants() on Cxx NativeModule (name = \"" + getName() +
+        "\").");
+  }
+
   folly::dynamic constants = folly::dynamic::object();
   for (auto &pair : module_->getConstants()) {
     constants.insert(std::move(pair.first), std::move(pair.second));
@@ -121,6 +133,12 @@ void CxxNativeModule::invoke(
         "Method ", method.name, " is synchronous but invoked asynchronously"));
   }
 
+  if (warnOnUsageLogger_) {
+    warnOnUsageLogger_(
+        "Calling " + method.name + "() on Cxx NativeModule (name = \"" +
+        getName() + "\").");
+  }
+
   if (params.size() < method.callbacks) {
     throw std::invalid_argument(folly::to<std::string>(
         "Expected ",
@@ -204,6 +222,12 @@ MethodCallResult CxxNativeModule::callSerializableNativeHook(
         "Method ", method.name, " is asynchronous but invoked synchronously"));
   }
 
+  if (warnOnUsageLogger_) {
+    warnOnUsageLogger_(
+        "Calling " + method.name + "() on Cxx NativeModule (name = \"" +
+        getName() + "\").");
+  }
+
   return method.syncFunc(std::move(args));
 }