Bubble original event rather than a new custom one

We decided we could use the `dragover` and `dragenter` events directly
instead of wrapping them with a custom one.  We're still calling `preventDefault()`
so we won't accidentally trigger any native behavior downstream.

Author: Bestra

src/file-attachment-element.ts

@@ -74,16 +74,6 @@ function onDragenter(event: DragEvent) {
     clearTimeout(dragging)
   }
 
-  const dragEvent = new CustomEvent('file-attachment-dragged', {
-    bubbles: true,
-    cancelable: true,
-    detail: {
-      dragEvent: event,
-      target
-    }
-  })
-  target.dispatchEvent(dragEvent)
-
   dragging = window.setTimeout(() => target.removeAttribute('hover'), 200)
 
   const transfer = event.dataTransfer
@@ -92,7 +82,6 @@ function onDragenter(event: DragEvent) {
   transfer.dropEffect = 'copy'
   target.setAttribute('hover', '')
 
-  event.stopPropagation()
   event.preventDefault()
 }
 

test/test.js

@@ -125,22 +125,34 @@ describe('file-attachment', function () {
       assert.equal(0, input.files.length)
     })
 
-    it('fires a file-attachment-dragged event on dragenter', async function () {
-      const listener = once('file-attachment-dragged')
-      const dragEvent = new Event('dragenter', {bubbles: true})
+    it('bubbles the dragenter event after cancelling its default behavior', async function () {
+      const dataTransfer = new DataTransfer()
+      const file = new File(['hubot'], 'test.txt', {type: 'text/plain'})
+      dataTransfer.items.add(file)
+
+      const dragEvent = new DragEvent('dragenter', {bubbles: true, cancelable: true, dataTransfer})
+
+      const listener = once('dragenter')
       input.dispatchEvent(dragEvent)
+
       const event = await listener
-      assert.equal(dragEvent, event.detail.dragEvent)
-      assert.equal(fileAttachment, event.detail.target)
+      assert.equal(dragEvent, event)
+      assert.equal(true, event.defaultPrevented)
     })
 
-    it('fires a file-attachment-dragged event on dragover', async function () {
-      const listener = once('file-attachment-dragged')
-      const dragEvent = new Event('dragover', {bubbles: true})
+    it('bubbles the dragover event after cancelling its default behavior', async function () {
+      const dataTransfer = new DataTransfer()
+      const file = new File(['hubot'], 'test.txt', {type: 'text/plain'})
+      dataTransfer.items.add(file)
+
+      const dragEvent = new DragEvent('dragover', {bubbles: true, cancelable: true, dataTransfer})
+
+      const listener = once('dragover')
       input.dispatchEvent(dragEvent)
+
       const event = await listener
-      assert.equal(dragEvent, event.detail.dragEvent)
-      assert.equal(fileAttachment, event.detail.target)
+      assert.equal(dragEvent, event)
+      assert.equal(true, event.defaultPrevented)
     })
   })
 })