[SVG2] Make transform, gradientTransform and patternTransform presentation attributes.

Spec:
http://www.w3.org/TR/css3-transforms/#svg-transform
http://www.w3.org/TR/css3-transforms/#svg-syntax
http://www.w3.org/TR/css3-transforms/#svg-gradient-transform-pattern-transform

BUG=369942

Review URL: https://codereview.chromium.org/423093014

git-svn-id: svn://svn.chromium.org/blink/trunk@179702 bbb929c8-8fbe-4397-9dbb-9b2b20218538