share a single ItemIconCache across the UI

src/ui/GameWorldView.cpp

@@ -197,11 +197,13 @@ QColor statusLightFill(ProductionStatus status, const StatusLightVisuals& sl)
 
 GameWorldView::GameWorldView(Simulation* sim, const GameConfig* config,
                              const VisualsConfig* visuals, const std::string& configDir,
-                             const ParsedReplay* replay, QWidget* parent)
+                             ItemIconCache* itemIcons, const ParsedReplay* replay,
+                             QWidget* parent)
     : QOpenGLWidget(parent)
     , m_sim(sim)
     , m_config(config)
     , m_visuals(visuals)
+    , m_itemIcons(itemIcons)
     , m_commandManager(*sim)
     , m_gameSpeedMultiplier(1.0)
     , m_prevNonZeroSpeed(1.0)
@@ -223,11 +225,6 @@ GameWorldView::GameWorldView(Simulation* sim, const GameConfig* config,
 
     loadBuildingIcons(configDir);
 
-    // Item icons live beside the config dir, mirroring the building icons
-    // (REQ-UI-ITEM-ICON, REQ-UI-WORLD-ICON).
-    m_itemIcons = std::make_unique<ItemIconCache>(QDir::cleanPath(
-        QString::fromStdString(configDir) + "/../icons/items"));
-
     m_renderTimer = new QTimer(this);
     m_renderTimer->setInterval(16);
     connect(m_renderTimer, &QTimer::timeout, this, &GameWorldView::onFrame);