In IE 11, nodes in MutationRecord.removedNodes are always empty when they're removed by setting innerHTML. This shim works around the issue by patching HTMLElement.innerHTML to remove each child node individually before setting the new value.

References:

• https://connect.microsoft.com/IE/feedback/details/817132/ie-11-childnodes-are-missing-from-mutationobserver-mutations-removednodes-after-setting-innerhtml
• WebReflection/document-register-element#101
• skatejs/skatejs#85