Fixed some gcalloc in the debug window

com.unity.render-pipelines.core/Editor/Debugging/DebugUIDrawer.cs

@@ -36,10 +36,12 @@ protected T Cast<T>(object o)
             where T : class
         {
             var casted = o as T;
-            string typeName = o == null ? "null" : o.GetType().ToString();
 
             if (casted == null)
+            {
+                string typeName = o == null ? "null" : o.GetType().ToString();
                 throw new InvalidOperationException("Can't cast " + typeName + " to " + typeof(T));
+            }
 
             return casted;
         }

com.unity.render-pipelines.high-definition/CHANGELOG.md

@@ -592,6 +592,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Fixed issue with sceneview camera settings not being saved after Editor restart.
 - Fixed issue when switching back to custom sensor type in physical camera settings (case 1244350).
 - Fixed a null ref exception when running playmode tests with the render pipeline debug window opened.
+- Fixed some GCAlloc in the debug window.
 
 ### Changed
 - Improve MIP selection for decals on Transparents

com.unity.render-pipelines.high-definition/Runtime/Debug/VolumeDebug.cs

@@ -123,15 +123,21 @@ public Type     selectedComponentType
             }
         }
 
+        static List<Type> s_ComponentTypes;
+
         /// <summary>List of Volume component types.</summary>
         static public List<Type> componentTypes
         {
             get
             {
-                return VolumeManager.instance.baseComponentTypes
+                if (s_ComponentTypes == null)
+                {
+                    s_ComponentTypes = VolumeManager.instance.baseComponentTypes
                     .Where(t => !t.IsDefined(typeof(VolumeComponentDeprecated), false))
                     .OrderBy(t => ComponentDisplayName(t))
                     .ToList();
+                }
+                return s_ComponentTypes;
             }
         }