Bug 883313 - Fix nsHTMLDocument::SetBody to call either ReplaceChild or AppendChild, not both. r=smaug, a=abillings
Bug 891424 - Directly remove nsCocoaWindow's from their parent in Destroy(). This allows us to stop implementing GetParent because the mac widget code has some assumptions about that always returning null. r=smichaud, a=lsblakk

This reverts implementing GetParent on nsCocoaWindow's (ie back out bug 869151) because the mac widget code has some assumptions about that. Instead we just remove nsCocoaWindow's from their mParent in Destroy() which will still keep bug 869151 fixed.
Bug 888607 - Correctly clear sub-frames. r=seth, a=bajaj
Bug 888607 - Test. r=seth, a=bajaj