Add fluent builders for more flexibly adding data to Shuffleboard (#1022)

wpilibc/src/main/native/include/frc/shuffleboard/SimpleWidget.h

@@ -0,0 +1,45 @@
+/*----------------------------------------------------------------------------*/
+/* Copyright (c) 2018 FIRST. All Rights Reserved.                             */
+/* Open Source Software - may be modified and shared by FRC teams. The code   */
+/* must be accompanied by the FIRST BSD license file in the root directory of */
+/* the project.                                                               */
+/*----------------------------------------------------------------------------*/
+
+#pragma once
+
+#include <memory>
+
+#include <networktables/NetworkTable.h>
+#include <networktables/NetworkTableEntry.h>
+#include <wpi/Twine.h>
+
+#include "frc/shuffleboard/ShuffleboardWidget.h"
+
+namespace frc {
+
+class ShuffleboardContainer;
+
+/**
+ * A Shuffleboard widget that handles a single data point such as a number or
+ * string.
+ */
+class SimpleWidget final : public ShuffleboardWidget<SimpleWidget> {
+ public:
+  SimpleWidget(ShuffleboardContainer& parent, const wpi::Twine& title);
+
+  /**
+   * Gets the NetworkTable entry that contains the data for this widget.
+   */
+  nt::NetworkTableEntry GetEntry();
+
+  void BuildInto(std::shared_ptr<nt::NetworkTable> parentTable,
+                 std::shared_ptr<nt::NetworkTable> metaTable) override;
+
+ private:
+  nt::NetworkTableEntry m_entry;
+  bool m_entryInitialized = false;
+
+  void ForceGenerate();
+};
+
+}  // namespace frc