Invalidate SVG 'transform' pres. attribute style even if not attached

When the 'transform' attribute was manipulated via its SVG DOM
representation (SVGTransformList), the
presentation-attribute-style-is-dirty flag would not be set unless the
element had been attached.
Reorder the contents of the 'transform' branch in
SVGGraphicsElement::svgAttributeChanged so that the presentation
attribute style is always dirtied regardless of attachment status.

BUG=701075

Review-Url: https://codereview.chromium.org/2745053005
Cr-Commit-Position: refs/heads/master@{#456696}
3 files changed