move to new ImageGenerator API

This will allow us to remove SK_SUPPORT_LEGACY_IMAGEGENERATORAPI

BUG=

Review URL: https://codereview.chromium.org/304353008

git-svn-id: svn://svn.chromium.org/blink/trunk@175168 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make importNode work when the XML document contains a CDATA section

Make importNode work when the XML document contains a CDATA section
by avoiding calling createCDATASection since createCDATASection
throws an exception for HTML Documents.

The new behavior matches Firefox.

BUG=340059

Review URL: https://codereview.chromium.org/167653002

git-svn-id: svn://svn.chromium.org/blink/trunk@175169 bbb929c8-8fbe-4397-9dbb-9b2b20218538