Revert "Re-factor VisibleSelectionTest for adding tests for composed tree version"

Revert "Re-factor VisibleSelectionTest for adding tests for composed tree version"

This reverts commit 52847e6579f5703d41a96349992b79f1ae258b98.

Reason for revert:
Breaks Android Builder (dbg) compilation,

http://build.chromium.org/p/chromium.webkit/builders/Android%20Builder%20(dbg)/builds/43678

(and Oilpan compilation.)

Original issue's description:
> Re-factor VisibleSelectionTest for adding tests for composed tree version
>
> This patch changes |VisibleSelectionTest| for adding tests for composed tree
> version easier with introducing shadow tree related tests.
>
> This patch also introduces |Node| and |Position| for ease of writing and
> debugging gTest.
>
> This patch is result of collaboration work with hajimehoshi@chromium.org
> for selection of web components. After this patch, we are going to implement
> another strategies for the composed tree. We've already
> prepared that at http://crrev.com/1009603011.
>
> BUG=275851
> TEST=n/a; No behavior changes.
>
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=194195

TBR=yosin,tkent
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=275851
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=194197

[sof, 2015-04-22 07:02:28]

The CQ bit was checked by sigbjornf@opera.com

[commit-bot: I haz the power, 2015-04-22 07:02:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1055633004/1

[commit-bot: I haz the power, 2015-04-22 07:03:36]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=194197