Unity-TransformInspector adding reset button for each property

TransformInspector.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;

// Reverse engineered UnityEditor.TransformInspector
[CanEditMultipleObjects, CustomEditor(typeof(Transform))]
public class TransformInspector : Editor {

	private const float FIELD_WIDTH = 300.0f;
	private const bool WIDE_MODE = true;

	private const float POSITION_MAX = 100000.0f;

	private static GUIContent positionGUIContent = new GUIContent(LocalString("")
		,LocalString("The local position of this Game Object relative to the parent."));
	private static GUIContent rotationGUIContent = new GUIContent(LocalString("")
		,LocalString("The local rotation of this Game Object relative to the parent."));
	private static GUIContent scaleGUIContent    = new GUIContent(LocalString("")
		,LocalString("The local scaling of this Game Object relative to the parent."));

	private static string positionWarningText = LocalString("Due to floating-point precision limitations, it is recommended to bring the world coordinates of the GameObject within a smaller range.");

	private SerializedProperty positionProperty;
	private SerializedProperty rotationProperty;
	private SerializedProperty scaleProperty;

	private static string LocalString(string text) {
		return text;
	}

	public void OnEnable() {
		this.positionProperty = this.serializedObject.FindProperty("m_LocalPosition");
		this.rotationProperty = this.serializedObject.FindProperty("m_LocalRotation");
		this.scaleProperty    = this.serializedObject.FindProperty("m_LocalScale");
	}

	public override void OnInspectorGUI() {
		EditorGUIUtility.wideMode = TransformInspector.WIDE_MODE;
		EditorGUIUtility.labelWidth = 50; //EditorGUIUtility.currentViewWidth - TransformInspector.FIELD_WIDTH; // align field to right of inspector

		this.serializedObject.Update();


		EditorGUILayout.BeginHorizontal();
		if (GUILayout.Button("P", GUILayout.Width(20))) {
			this.positionProperty.vector3Value = Vector3.zero;
		}
		EditorGUILayout.PropertyField(this.positionProperty, positionGUIContent);
		EditorGUILayout.EndHorizontal();

		EditorGUILayout.BeginHorizontal();
		if (GUILayout.Button("R", GUILayout.Width(20))) {
			this.rotationProperty.quaternionValue = Quaternion.identity;
		}
		this.RotationPropertyField(   this.rotationProperty, rotationGUIContent);
		EditorGUILayout.EndHorizontal();


		EditorGUILayout.BeginHorizontal();
		if (GUILayout.Button("S", GUILayout.Width(20))) {
			this.scaleProperty.vector3Value = Vector3.one;
		}
		EditorGUILayout.PropertyField(this.scaleProperty,    scaleGUIContent);
		EditorGUILayout.EndHorizontal();

		if (!ValidatePosition(((Transform) this.target).position)) {
			EditorGUILayout.HelpBox(positionWarningText, MessageType.Warning);
		}

		this.serializedObject.ApplyModifiedProperties();
	}

	private bool ValidatePosition(Vector3 position) {
		if (Mathf.Abs(position.x) > TransformInspector.POSITION_MAX) return false;
		if (Mathf.Abs(position.y) > TransformInspector.POSITION_MAX) return false;
		if (Mathf.Abs(position.z) > TransformInspector.POSITION_MAX) return false;
		return true;
	}

	private void RotationPropertyField(SerializedProperty rotationProperty, GUIContent content) {
		Transform transform = (Transform) this.targets[0];
		Quaternion localRotation = transform.localRotation;
		foreach (UnityEngine.Object t in (UnityEngine.Object[]) this.targets) {
			if (!SameRotation(localRotation, ((Transform) t).localRotation)) {
				EditorGUI.showMixedValue = true;
				break;
			}
		}

		EditorGUI.BeginChangeCheck();

		Vector3 eulerAngles = EditorGUILayout.Vector3Field(content, localRotation.eulerAngles);

		if (EditorGUI.EndChangeCheck()) {
			Undo.RecordObjects(this.targets, "Rotation Changed");
			foreach (UnityEngine.Object obj in this.targets) {
				Transform t = (Transform) obj;
				t.localEulerAngles = eulerAngles;
			}
			rotationProperty.serializedObject.SetIsDifferentCacheDirty();
		}

		EditorGUI.showMixedValue = false;
	}

	private bool SameRotation(Quaternion rot1, Quaternion rot2) {
		if (rot1.x != rot2.x) return false;
		if (rot1.y != rot2.y) return false;
		if (rot1.z != rot2.z) return false;
		if (rot1.w != rot2.w) return false;
		return true;
	}
}