Reland "[LayoutNG] Dump NGPhysicalTextFragment"

This is a reland of 76361c1aa7af1296ec50b72d6b853561d6f30c66

Includes MSVC warning fix at CL:867912, thanks to mstensho@.

Original change's description:
> [LayoutNG] Dump NGPhysicalTextFragment
>
> This patch dumps NGPhysicalTextFragment associated with LayoutText
> in the same format as InlineTextBox to help reviewing test failures
> in LayoutNG.
>
> LayoutTreeAsText supports RootInlineBox and InlineFlowBox, but they
> are not supported for LayoutNG yet. They may be added if they appear
> a lot in the text failures, but I have not reviewed them yet.
>
> Bug: 591099
> Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_layout_ng
> Change-Id: I80d6540794cc3630108e02d63a4f749e76e505d1
> Reviewed-on: https://chromium-review.googlesource.com/864962
> Commit-Queue: Koji Ishii <kojii@chromium.org>
> Reviewed-by: Xiaocheng Hu <xiaochengh@chromium.org>
> Reviewed-by: Emil A Eklund <eae@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#529371}

TBR=mstensho@chromium.org

Bug: 591099
Change-Id: Ifcad17b791a21a790ee7558b9bae7e8fff791dda
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_layout_ng
Reviewed-on: https://chromium-review.googlesource.com/868191
Reviewed-by: Emil A Eklund <eae@chromium.org>
Commit-Queue: Emil A Eklund <eae@chromium.org>
Cr-Commit-Position: refs/heads/master@{#529439}
111 files changed