[glass] Add glass: an application for display of robot data

This reuses many pieces of the current simulation GUI.  The common pieces have
been refactored into the libglass library.

The libglass library is designed to be usable for other standalone data
visualization applications (e.g. viewing data logs).

The name "glass" comes from "glass cockpit", as the application features
several multi-function displays that can be adjusted to display robot
information as needed.

simulation/halsim_gui/src/main/native/cpp/TimingGui.cpp

@@ -7,6 +7,9 @@
 
 #include "TimingGui.h"
 
+#include <glass/Model.h>
+#include <glass/View.h>
+
 #include <cstdio>
 #include <cstring>
 #include <vector>
@@ -20,6 +23,14 @@
 
 using namespace halsimgui;
 
+namespace {
+class TimingModel : public glass::Model {
+ public:
+  void Update() override {}
+  bool Exists() override { return true; }
+};
+}  // namespace
+
 static void DisplayTiming() {
   int32_t status = 0;
   uint64_t curTime = HAL_GetFPGATime(&status);
@@ -55,7 +66,14 @@ static void DisplayTiming() {
 }
 
 void TimingGui::Initialize() {
-  HALSimGui::AddWindow("Timing", DisplayTiming,
-                       ImGuiWindowFlags_AlwaysAutoResize);
-  HALSimGui::SetDefaultWindowPos("Timing", 5, 150);
+  HALSimGui::halProvider.Register(
+      "Timing", [] { return true; },
+      [] { return std::make_unique<TimingModel>(); },
+      [](glass::Window* win, glass::Model* model) {
+        win->DisableRenamePopup();
+        win->SetFlags(ImGuiWindowFlags_AlwaysAutoResize);
+        win->SetDefaultPos(5, 150);
+        return glass::MakeFunctionView(DisplayTiming);
+      });
+  HALSimGui::halProvider.ShowDefault("Timing");
 }