fabric/debug module and DebugStringConvertible class

Summary:
This is a very first diff in a series of undefined length implementing React Native Shadow Tree infra in C++.
All Shadow Nodes, Props and etc. implements `DebugStringConvertible`.

Authored by shergin

Reviewed By: shergin

Differential Revision: D7163868

fbshipit-source-id: 9c001aa5bd0723f709a07b1833f512c51e3bec11

ReactCommon/fabric/debug/DebugStringConvertibleItem.cpp

@@ -0,0 +1,41 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "DebugStringConvertibleItem.h"
+
+namespace facebook {
+namespace react {
+
+DebugStringConvertibleItem::DebugStringConvertibleItem(
+  const std::string &name,
+  const std::string &value,
+  const SharedDebugStringConvertibleList &props,
+  const SharedDebugStringConvertibleList &children
+):
+  name_(name),
+  value_(value),
+  props_(props),
+  children_(children) {}
+
+std::string DebugStringConvertibleItem::getDebugName() const {
+  return name_;
+}
+
+std::string DebugStringConvertibleItem::getDebugValue() const {
+  return value_;
+}
+
+SharedDebugStringConvertibleList DebugStringConvertibleItem::getDebugProps() const {
+  return props_;
+}
+
+SharedDebugStringConvertibleList DebugStringConvertibleItem::getDebugChildren() const {
+  return children_;
+}
+
+} // namespace react
+} // namespace facebook