- Updated FrameRate/Time debug view with using SmoothDT

- Workaround for destroyed GameObjects being accessed when leaving playmode.

Assets/ScriptableRenderPipeline/Core/Debugging/DebugPanelUI.cs

 
         public void Update()
         {
+            // A bit dirty... this will happen when we exit playmode.
+            // The problem happens when the persistent menu is not empty and we leave playmode.
+            // In this case, the gameObjects will be destroyed but not the ItemUIs (because we can't know when we exit playmode)
+            // To avoid accessing destroyed GameObjects we test the root...
+            if (m_Root == null)
+                return;
+
             foreach (var itemUI in m_ItemsUI)
             {
                 if (itemUI.dynamicDisplay)

Assets/ScriptableRenderPipeline/HDRenderPipeline/Debug/DebugDisplay.cs

 
         public void RegisterDebug()
         {
-            DebugMenuManager.instance.AddDebugItem<float>("Display Stats", "Frame Rate", () => 1.0f / Time.deltaTime, null, true);
-            DebugMenuManager.instance.AddDebugItem<float>("Display Stats", "Frame Time", () => Time.deltaTime * 1000.0f, null, true);
+            DebugMenuManager.instance.AddDebugItem<float>("Display Stats", "Frame Rate", () => 1.0f / Time.smoothDeltaTime, null, true);
+            DebugMenuManager.instance.AddDebugItem<float>("Display Stats", "Frame Time (ms)", () => Time.smoothDeltaTime * 1000.0f, null, true);
 
             DebugMenuManager.instance.AddDebugItem<int>("Material", "Material",() => materialDebugSettings.debugViewMaterial, (value) => SetDebugViewMaterial((int)value), false, new DebugItemHandlerIntEnum(DebugDisplaySettings.debugViewMaterialStrings, DebugDisplaySettings.debugViewMaterialValues));
             DebugMenuManager.instance.AddDebugItem<int>("Material", "Engine",() => materialDebugSettings.debugViewEngine, (value) => SetDebugViewEngine((int)value), false, new DebugItemHandlerIntEnum(DebugDisplaySettings.debugViewEngineStrings, DebugDisplaySettings.debugViewEngineValues));