Bug 977950.  Fix dragging of text to work again.  r=smaug
Bug 952890 part 1.  Make WebIDL sequence JS to C++ conversions use for-of iteration, not length/index gets.  r=peterv
Bug 952890 part 2.  Remove the IsArrayLike method, since it no longer matches any spec concept.  r=peterv
Bug 952596.  HasActiveDocument should just clearly assert that it's only called on inner windows.  r=smaug