Add "Remove HD *" context menu items for light / reflection probe / camera

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Camera/HDAdditionalCameraData.cs

-using UnityEngine.Serialization;
+using UnityEngine.Serialization;
 
 namespace UnityEngine.Experimental.Rendering.HDPipeline
 {
 
         void UnRegisterDebug()
         {
+            if (m_camera == null) return;
+
             if (m_IsDebugRegistered)
             {
                 if (m_camera.cameraType != CameraType.Preview && m_camera.cameraType != CameraType.Reflection)
             // When LDR, unity render in 8bitSRGB, then do a final shader with sRGB conversion
             // What should be done is just in our Post process we convert to sRGB and store in a linear 10bit, but require C++ change...
             m_camera = GetComponent<Camera>();
+            if (m_camera == null) return;
             m_camera.allowHDR = false;
 
             //  Tag as dirty so frameSettings are correctly initialize at next HDRenderPipeline.Render() call

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Camera/HDCameraEditor.cs

-using System;
+using System;
+using UnityEngine.Assertions;
 using UnityEngine.Experimental.Rendering;
 using UnityEngine.Experimental.Rendering.HDPipeline;
 using UnityEngine.Rendering.PostProcessing;
     [CanEditMultipleObjects]
     partial class HDCameraEditor : Editor
     {
+        [MenuItem("CONTEXT/Camera/Remove HD Camera", false, 0)]
+        static void RemoveLight(MenuCommand menuCommand)
+        {
+            GameObject go = ((Camera)menuCommand.context).gameObject;
+
+            Assert.IsNotNull(go);
+
+            Undo.SetCurrentGroupName("Remove HD Camera");
+            Undo.DestroyObjectImmediate(go.GetComponent<Camera>());
+            Undo.DestroyObjectImmediate(go.GetComponent<HDAdditionalCameraData>());
+        }
+
         SerializedHDCamera m_SerializedCamera;
         HDCameraUI m_UIState = new HDCameraUI();
 

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Lighting/HDLightEditor.cs

 using System;
 using UnityEngine;
+using UnityEngine.Assertions;
 using UnityEngine.Experimental.Rendering;
 using UnityEngine.Experimental.Rendering.HDPipeline;
 
     [CustomEditorForRenderPipeline(typeof(Light), typeof(HDRenderPipelineAsset))]
     sealed partial class HDLightEditor : LightEditor
     {
+        [MenuItem("CONTEXT/Light/Remove HD Light", false,0)]
+        static void RemoveLight(MenuCommand menuCommand)
+        {
+            GameObject go = ( (Light) menuCommand.context ).gameObject;
+
+            Assert.IsNotNull(go);
+
+            Undo.IncrementCurrentGroup();
+            Undo.DestroyObjectImmediate(go.GetComponent<Light>());
+            Undo.DestroyObjectImmediate(go.GetComponent<HDAdditionalLightData>());
+            Undo.DestroyObjectImmediate(go.GetComponent<AdditionalShadowData>());
+        }
+
         sealed class SerializedLightData
         {
             public SerializedProperty directionalIntensity;

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Lighting/Reflection/HDReflectionProbeEditor.ProbeUtility.cs

-using UnityEngine;
+using UnityEngine;
 using UnityEngine.Experimental.Rendering;
 using Object = UnityEngine.Object;
 
     {
         void ChangeVisibilityOfAllTargets(bool visibility)
         {
+            if (targets.Length == 0) return;
+
-                var p = (ReflectionProbe)targets[i];
-                HDReflectionProbeEditorUtility.ChangeVisibility(p, visibility);
+                if (targets[i] != null)
+                {
+                    var p = (ReflectionProbe)targets[i];
+                    HDReflectionProbeEditorUtility.ChangeVisibility(p, visibility);
+                }
             }
         }
 

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Editor/Lighting/Reflection/HDReflectionProbeEditor.cs

-using System.Collections.Generic;
+using System.Collections.Generic;
+using UnityEngine.Assertions;
 using UnityEngine.Experimental.Rendering;
 using UnityEngine.Experimental.Rendering.HDPipeline;
 using UnityEngine.Rendering;
     [CanEditMultipleObjects]
     partial class HDReflectionProbeEditor : Editor
     {
+        [MenuItem("CONTEXT/ReflectionProbe/Remove HD Reflection Probe", false, 0)]
+        static void RemoveLight(MenuCommand menuCommand)
+        {
+            GameObject go = ((ReflectionProbe)menuCommand.context).gameObject;
+
+            Assert.IsNotNull(go);
+
+            Undo.SetCurrentGroupName("Remove HD Reflection Probe");
+            Undo.DestroyObjectImmediate(go.GetComponent<ReflectionProbe>());
+            Undo.DestroyObjectImmediate(go.GetComponent<HDAdditionalReflectionData>());
+            Undo.DestroyObjectImmediate(go.GetComponent<MeshRenderer>());
+            Undo.DestroyObjectImmediate(go.GetComponent<MeshFilter>());
+        }
+
         static Dictionary<ReflectionProbe, HDReflectionProbeEditor> s_ReflectionProbeEditors = new Dictionary<ReflectionProbe, HDReflectionProbeEditor>();
 
         static HDReflectionProbeEditor GetEditorFor(ReflectionProbe p)