Remove scrollOffsetX and scrollOffsetY from RenderLayer

Also removed adjustedScrollOffset that
depended on the previous functions.

BUG=260899

Review URL: https://codereview.chromium.org/27536012

git-svn-id: svn://svn.chromium.org/blink/trunk@159925 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move the logic to handle setHostAndPort to KURL.cpp

This was duplicated in DOMURLUtils.

There is one minor change. If setting location.host to "abc:" it used
remove the port, now it sets it to 0, to align with other usages of
URLs exposed to the web.

BUG=None

Review URL: https://codereview.chromium.org/27557005

git-svn-id: svn://svn.chromium.org/blink/trunk@159926 bbb929c8-8fbe-4397-9dbb-9b2b20218538