Revert "Reland "Make NGOffsetMapping available for non-LayoutNG LayoutBlockFlow""

This reverts commit b3a685fda9dc74255e5c44b46472eb89e05f7873.

Reason for revert:

Findit (https://goo.gl/kROfz5) identified CL at revision 606525 as the
culprit for failures in the build cycles as shown on:
https://findit-for-me.appspot.com/waterfall/culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyRAsSDVdmU3VzcGVjdGVkQ0wiMWNocm9taXVtL2IzYTY4NWZkYTlkYzc0MjU1ZTVjNDRiNDY0NzJlYjg5ZTA1Zjc4NzMM

Sample Failed Build: https://ci.chromium.org/buildbot/chromium.linux/Cast%20Audio%20Linux/25051

Sample Failed Step: webkit_unit_tests

Original change's description:
> Reland "Make NGOffsetMapping available for non-LayoutNG LayoutBlockFlow"
> 
> This is a reland of b43c6fca4349b7f2ff53b41926f5d7cb42ee4e0f
> 
> Cannot reproduce the failures locally, nor in CQ.
> 
> Try to reland the same CL to see if it was a flake.
> 
> Original change's description:
> > Make NGOffsetMapping available for non-LayoutNG LayoutBlockFlow
> >
> > This patch allows computing NGOffsetMapping for legacy inline
> > formatting context.
> >
> > For an experimental project "Invisible DOM"[1][2] to support
> > the find-in-page feature, it is needed to compute the text
> > content with whitespace collapsing applied, along with the
> > mapping to the DOM offset. This patch adds an API to compute
> > NGOffsetMapping even when the LayoutBlockFlow is not laid out
> > by LayoutNG for that purpose.
> >
> > Note that the project is still in the early phase. We may
> > revisit the design as it moves forward.
> >
> > [1] https://github.com/rakina/searchable-invisible-dom
> > [2] https://www.chromestatus.com/feature/5105291213406208
> >
> > Bug: 636993, 873057
> > Change-Id: I101b411960813a7b9b5c9c6e2db85d28737af882
> > Reviewed-on: https://chromium-review.googlesource.com/c/1322184
> > Reviewed-by: Xiaocheng Hu <xiaochengh@chromium.org>
> > Reviewed-by: Emil A Eklund <eae@chromium.org>
> > Reviewed-by: Yoshifumi Inoue <yosin@chromium.org>
> > Reviewed-by: Rakina Zata Amni <rakina@chromium.org>
> > Commit-Queue: Koji Ishii <kojii@chromium.org>
> > Cr-Commit-Position: refs/heads/master@{#606292}
> 
> TBR=yoshin@chromium.org, eae@chromium.org
> 
> Bug: 636993, 873057
> Change-Id: I241c6e9163add4000fa078c5d70a62b89acea9ac
> Reviewed-on: https://chromium-review.googlesource.com/c/1326343
> Reviewed-by: Emil A Eklund <eae@chromium.org>
> Commit-Queue: Emil A Eklund <eae@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#606525}

Change-Id: If3d6c17f4cf7ba241380ab3906da0a8029720a0b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 636993, 873057
Reviewed-on: https://chromium-review.googlesource.com/c/1327401
Cr-Commit-Position: refs/heads/master@{#606547}
3 files changed