Let's avoid the confusion and name all these new APIs that can post both
to document and window to have 'Window' in their name. The ones without
window are the old APIs. In future, we can have
postWindow{Key,Mouse}Event() to post to both document and window and
deprecate the existing post{Key,Mouse}Event()s.

Change-Id: I1f55386e7790e9c5b5d023b8831f3cd1e6faa2bb