Dropping elemental-forms and swapping out with imgui.

Too much code for such little use. This should simplify porting.

src/xenia/ui/imgui_dialog.cc

@@ -0,0 +1,93 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2015 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#include "xenia/ui/imgui_dialog.h"
+
+#include "third_party/imgui/imgui.h"
+#include "xenia/base/assert.h"
+#include "xenia/ui/window.h"
+
+namespace xe {
+namespace ui {
+
+ImGuiDialog::ImGuiDialog(Window* window) : window_(window) {
+  window_->AttachListener(this);
+  had_imgui_active_ = window_->is_imgui_input_enabled();
+  window_->set_imgui_input_enabled(true);
+}
+
+ImGuiDialog::~ImGuiDialog() {
+  window_->set_imgui_input_enabled(had_imgui_active_);
+  window_->DetachListener(this);
+  for (auto fence : waiting_fences_) {
+    fence->Signal();
+  }
+}
+
+void ImGuiDialog::Then(xe::threading::Fence* fence) {
+  waiting_fences_.push_back(fence);
+}
+
+void ImGuiDialog::Close() { has_close_pending_ = true; }
+
+ImGuiIO& ImGuiDialog::GetIO() { return window_->imgui_drawer()->GetIO(); }
+
+void ImGuiDialog::OnPaint(UIEvent* e) {
+  // Keep imgui rendering every frame.
+  window_->Invalidate();
+
+  // Draw UI.
+  OnDraw(GetIO());
+
+  // Check to see if the UI closed itself and needs to be deleted.
+  if (has_close_pending_) {
+    OnClose();
+    delete this;
+  }
+}
+
+class MessageBoxDialog : public ImGuiDialog {
+ public:
+  MessageBoxDialog(Window* window, std::string title, std::string body)
+      : ImGuiDialog(window), title_(std::move(title)), body_(std::move(body)) {}
+
+  void OnDraw(ImGuiIO& io) override {
+    if (!has_opened_) {
+      ImGui::OpenPopup(title_.c_str());
+      has_opened_ = true;
+    }
+    if (ImGui::BeginPopupModal(title_.c_str(), nullptr,
+                               ImGuiWindowFlags_AlwaysAutoResize)) {
+      char* text = const_cast<char*>(body_.c_str());
+      ImGui::InputTextMultiline(
+          "##body", text, body_.size(), ImVec2(0, 0),
+          ImGuiInputTextFlags_AutoSelectAll | ImGuiInputTextFlags_ReadOnly);
+      if (ImGui::Button("OK")) {
+        ImGui::CloseCurrentPopup();
+        Close();
+      }
+      ImGui::EndPopup();
+    } else {
+      Close();
+    }
+  }
+
+ private:
+  bool has_opened_ = false;
+  std::string title_;
+  std::string body_;
+};
+
+ImGuiDialog* ImGuiDialog::ShowMessageBox(Window* window, std::string title,
+                                         std::string body) {
+  return new MessageBoxDialog(window, std::move(title), std::move(body));
+}
+
+}  // namespace ui
+}  // namespace xe