Issue 115444  has been merged into this issue.

Acording to <ruby>'s layout tree:
layoutRuby(block/inline)
    layoutRubyRun(inline-block)
        layoutRubyBase(block)
            layoutInline(<rb>)
                text
        layoutRubyText(block, <rt>)
            text

LayoutRubyRun is inline-block, and we will create a cluster for it. So autosize will be broken by this cluster.

Maybe we could use the similar design as inflateAutoTable:
when autosizing <ruby>:
  1. skip inline-block objects(rubyrun)
  2. use "DescendToInnerBlocks" behavior to autosize inner content

more detail :)
https://codereview.chromium.org/2683553002

Thank you for working on this. :)

The approach in #3 sounds ok to me.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/082b073b26e5f408462e4fd1f229d7614ace4364

commit 082b073b26e5f408462e4fd1f229d7614ace4364
Author: cathiechen <cathiechen@tencent.com>
Date: Thu Feb 16 08:30:37 2017

Fix not autosizing ruby elements issue.

RubyRun is inline-block. When inflate ruby, skip rubyRun and inflate all rubyRun's inner blocks.

BUG= 688561 

Review-Url: https://codereview.chromium.org/2683553002
Cr-Commit-Position: refs/heads/master@{#450897}

[modify] https://crrev.com/082b073b26e5f408462e4fd1f229d7614ace4364/third_party/WebKit/Source/core/layout/LayoutText.h
[modify] https://crrev.com/082b073b26e5f408462e4fd1f229d7614ace4364/third_party/WebKit/Source/core/layout/TextAutosizer.cpp
[modify] https://crrev.com/082b073b26e5f408462e4fd1f229d7614ace4364/third_party/WebKit/Source/core/layout/TextAutosizerTest.cpp

 Issue 400828  has been merged into this issue.