Remove ancestor walk for non-SVG RenderObjects in willBeRemovedFromTree()

Remove ancestor walk for non-SVG RenderObjects in willBeRemovedFromTree()

This patch removes the recursive setNeedsBoundariesUpdate() calls
that were done in RenderObject::willBeRemovedFromTree().

This patch has three main components:
1) The virtual RenderObject::needsBoundariesUpdate() has been removed
as it was never called.
2) The virtual RenderObject::isSVG() has been added for determining
whether a RenderObject is an SVG renderer. All SVG renderers have
been updated to return true for isSVG(). See the following diagram
for more information:
https://docs.google.com/a/chromium.org/drawings/d/1nayJX5XcclYj_-blbVuakVNjVWdRAzC5i5s6xBeHfzA/edit
3) RenderObject::willBeRemovedFromTree() now only calls
setNeedsBoundariesUpdate() if the parent renderer is SVG.

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=164056

[ojan, 2013-12-18 00:17:34]

lgtm

[commit-bot: I haz the power, 2013-12-18 00:17:48]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/pdr@chromium.org/108203005/20001

[esprehn, 2013-12-18 00:24:43]

amazing! Thank you. lgtm

[commit-bot: I haz the power, 2013-12-18 04:42:41]

Change committed as 164056