Add support for shadow elements

[diego-fernandez-santos]

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Atoms checks if an element is still attached to the DOM before every interaction. This check is done here. The problem is that it doesn't take into account shadow elements. These elements doesn't have a parentNode but they can still be attached to the DOM, for example shadowRoot elements.

If you try to interact with WebComponents in IPhone an "Element is no longer attached to the DOM" error would be raised.

I do this pull request in this branch because this is the current version that appium-remote-debugger currently using.

You can replicate this problem directly in the browser following the next steps:

• Go to https://shop.polymer-project.org/
• Open the inspector console and run the following script:

var doc = { documentElement : document }

  var element = document
    .querySelector('shop-app').shadowRoot
    .querySelector('shop-home').shadowRoot
    .querySelector('shop-button a');

  function getElementIfAttached(el) {
    var node = el;
    while (node) {
      if (node == doc.documentElement) {
        return el;
      }    
      node = node.parentNode;
    }
  }

  getElementIfAttached(element)

You can see that getElementIfAttached doesn't return the element although the shop-button is still attached to the DOM.

[CLAassistant]

All committers have signed the CLA.

[AutomatedTester]

instead of host I think that you want to node.ownerDocument to check if fragment is still attached.

Does this work on ShadowDOM as they are not document fragments

[diego-fernandez-santos]

I did the change.

I use that other way to try to keep the same code style. I think that it was valid (according to the last W3C). However I think that your recommendation is faster.

[imurchie]

This latest iteration doesn't work on MobileSafari, on any version of iOS I try. The first solution did work. At the point of failure, node.ownerDocument.parentNode does not exist but node.host.parentNode does.