Improve iframe support

[taye]

Event listeners are no longer automatically added to the parent window if the script is loaded in an iframe with a parent of the same origin to avoid potential memory leaks. preventDefault is no longer called on down events with the 'auto' setting. This allows mouse move and up events to be fired on the iframe even when the mouse is dragged outside the iframe borders and over the parent document.

interact.addDocument(document) and interact.removeDocument(document) methods have been added to allow listening to different documents, e.g:

// try to listen to events on the parent document if this is an iframe
try {
  if (window.frameElement) {
    const parentDoc = window.frameElement.ownerDocument;
    const parentWindow = parentDoc.defaultView;

    interact.addDocument(parentDoc);
    parentWindow.addEventListener('unload', function () { interact.removeDocument(parentDoc); });
  }
}
catch (error) {}

Close #311
Close #312

[taye]

@sixinli I've made a more thorough fix for you issue. Please try building this branch to see if it works and if any other problems appear.

[sixinli]

Hi @taye thanks for the fix! I am trying to test it out, but for some reason I keep getting

Uncaught TypeError: domUtils.isElement is not a function 

Is there anything that I should be aware of in order to test it out?

[sixinli]

Hi @taye, the fix works in my local (no more mem leak yay!) after rebasing on top of master with your recent commit. Thanks a ton again for pushing this forward!

[taye]

Sorry I forgot to mention the commit yesterday. I'm glad you spotted it early. Thanks for reporting and testing!