bindings: Fixes wrong comments in ScriptWrappable.h

I misunderstood about NoInterfaceObject and why SVGFilterPrimitiveStandardAttributes doesn't have corresponding V8T.{h,cpp}.  This CL fixes comments about it.

BUG=235436

Review URL: https://codereview.chromium.org/531293003

git-svn-id: svn://svn.chromium.org/blink/trunk@181300 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Check CSSParserValue::id instead of CSSParserValue::string where possible

BUG=404023

Review URL: https://codereview.chromium.org/537443002

git-svn-id: svn://svn.chromium.org/blink/trunk@181301 bbb929c8-8fbe-4397-9dbb-9b2b20218538