Add project files.

tests/editor_headless/stubs/imgui_internal.h

@@ -0,0 +1,13 @@
+#pragma once
+#include "imgui.h"
+struct ImGuiDockNode;
+enum ImGuiDockNodeFlagsPrivate_ { ImGuiDockNodeFlags_DockSpace = 1 << 10 };
+namespace ImGui {
+ImGuiDockNode *DockBuilderGetNode(ImGuiID node_id);
+void DockBuilderRemoveNode(ImGuiID node_id);
+ImGuiID DockBuilderAddNode(ImGuiID node_id = 0, ImGuiDockNodeFlags flags = 0);
+void DockBuilderSetNodeSize(ImGuiID node_id, ImVec2 size);
+ImGuiID DockBuilderSplitNode(ImGuiID node_id, ImGuiDir split_dir, float size_ratio_for_node_at_dir, ImGuiID *out_id_at_dir, ImGuiID *out_id_at_opposite_dir);
+void DockBuilderDockWindow(const char *window_name, ImGuiID node_id);
+void DockBuilderFinish(ImGuiID node_id);
+}