Copy and paste sprite physics shapes between TextureImporter, SpriteRenderer and PolygonCollider2D using their context menus.

SpriteShapeUtils.cs

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

#if UNITY_EDITOR
using UnityEditor;

public class SpriteShapeUtils
{
    static List<Vector2>[] shapesByIndex = new List<Vector2>[0];

    [MenuItem("CONTEXT/TextureImporter/Copy Physics Shape", priority = 110)]
    static void CopyShapeFromImporter(MenuCommand command)
    {
        var importer = command.context as TextureImporter;
        var sprite = AssetDatabase.LoadAssetAtPath<Sprite>(importer.assetPath);

        CopyShapeFromSprite(sprite);
    }

    [MenuItem("CONTEXT/SpriteRenderer/Copy Physics Shape", priority = 110)]
    static void CopyShapeFromSpriteRenderer(MenuCommand command)
    {
        var renderer = command.context as SpriteRenderer;

        CopyShapeFromSprite(renderer.sprite);
    }

    [MenuItem("CONTEXT/PolygonCollider2D/Copy Physics Shape", priority = 110)]
    static void CopyShapeFromCollider(MenuCommand command)
    {
        var collider = command.context as PolygonCollider2D;

        shapesByIndex = new List<Vector2>[collider.pathCount];

        for (int s = 0; s < shapesByIndex.Length; s++)
        {
            shapesByIndex[s] = new List<Vector2>(collider.GetPath(s));
        }
    }

    [MenuItem("CONTEXT/PolygonCollider2D/Paste Physics Shape", priority = 110)]
    static void PasteShapeIntoCollider(MenuCommand command)
    {
        var collider = command.context as PolygonCollider2D;

        collider.pathCount = shapesByIndex.Length;

        for (int s = 0; s < shapesByIndex.Length; s++)
        {
            collider.SetPath(s, shapesByIndex[s].ToArray());
        }
    }

    [MenuItem("CONTEXT/PolygonCollider2D/Use Sprite Physics Shape", priority = 110)]
    static void UseSpriteShape(MenuCommand command)
    {
        var collider = command.context as PolygonCollider2D;

        //this checks for SpriteRenderer upwards through the hierarchy (starting at the current GameObject)
        var sprite = collider.GetComponentInParent<SpriteRenderer>()?.sprite;

        CopyShapeFromSprite(sprite);
        PasteShapeIntoCollider(command);
    }

    private static void CopyShapeFromSprite(Sprite sprite)
    {
        if (sprite == null)
        {
            Debug.LogWarning("No Sprite found!");
            return;
        }

        shapesByIndex = new List<Vector2>[sprite.GetPhysicsShapeCount()];

        for (int s = 0; s < sprite.GetPhysicsShapeCount(); s++)
        {
            shapesByIndex[s] = new List<Vector2>();
            sprite.GetPhysicsShape(s, shapesByIndex[s]);
        }
    }
}

#endif