Node.replaceChild and Node.removeChild do not use custom binding anymore

This CL made those two methods use code generation
by removing Custom keyword from Node.idl
Then enabled interface type checking so appropriate TypeError
will be thrown as per sepc.

SPEC: http://www.w3.org/TR/WebIDL/#es-interface

TEST=fast/dom/Document/replaceChild-null-oldChild.html
    ,fast/events/remove-target-with-shadow-in-drag.html

Review URL: https://codereview.chromium.org/385073015

git-svn-id: svn://svn.chromium.org/blink/trunk@178000 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: ViewportControl.scrollIntoView synchronously updates viewport

This patch makes ViewportControl.scrollIntoView to synchronously update
its viewport.

As a result, it becomes legit to fetch rendered element
via ViewportControl.renderedElementAt after bringing it into viewport.
(that's what FilteredItemSelectionDialog does in its _updateSelection
method)

BUG=393432
R=aandrey

Review URL: https://codereview.chromium.org/389563003

git-svn-id: svn://svn.chromium.org/blink/trunk@178001 bbb929c8-8fbe-4397-9dbb-9b2b20218538