DevTools: Fix scrollbars being stuck in "Edit as html" editor

This patch fixes the regression issue implied by migration to CodeMirror
as an editor for this functionality. The core problem is that its
cursor is not native, so we have to sync native scrollbars with cursor
manually.

BUG=263737

Review URL: https://chromiumcodereview.appspot.com/21088002

git-svn-id: svn://svn.chromium.org/blink/trunk@155092 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Early return if animations should not apply in resetAnimatedType()

This is a merge of a change by Renata Hodovan in wkbug.com/118744

This patch early-returns if animations should not apply in
SVGAnimateElement::resetAnimatedType, preventing an assert in
SVGAniamtedType::valueAsString.

Review URL: https://chromiumcodereview.appspot.com/21095003

git-svn-id: svn://svn.chromium.org/blink/trunk@155093 bbb929c8-8fbe-4397-9dbb-9b2b20218538