Bug 923193. Make transform-origin on SVG elements use the SVG bbox as the reference rectangle. r=heycam

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extra : rebase_source : f4f620acc51e14625f45b8022385d8a1112fd086
Bug 926706. When nsGfxScrollFrameInner::UpdateOverflow decides we need to update the scrollbars, don't reflow the scrollframe with NS_FRAME_IS_DIRTY since that reflows all descendants. Just reflow the frame itself and don't dirty anything else. r=tn