How does Chrome decide what to highlight when you double-click Japanese text?

If you double-click English text in Chrome, the whitespace-delimited word you clicked on is highlighted. This is not surprising. However, the other day I was clicking while reading some text in Japanese and noticed that some words were highlighted at word boundaries, even though Japanese doesn't have spaces. Here's some example text: どこで生れたかとんと見当がつかぬ。何でも薄暗いじめじめした所でニャーニャー泣いていた事だけは記憶している。 For exampl

[mohri]

“v8 has a non-standard multi-language word segmenter and it handles Japanese.” へええ

[nakag0711]

精度が低いのであまり意味はなさそうだな

[tengo1985]

へえ

[yarumato]

“currently 315,671 total Chinese/Japanese words in the list.　'どこで生れたかとんと見当がつかぬ。何でも薄暗い')) // ["どこ", "で", "生れ", "たか", "とんと", "見当", "が", "つ", "か", "ぬ", "。", "何でも", "薄暗い",”

[peketamin]

マジか

[yamadar]

ICU=International Components for Unicode。大学や治療室では無い。

[yujiorama]

ICU の辞書式単語分割機能を使ってる

[Fushihara]

クロムで日本語のテキストをダブルcした時の自動選択の範囲の基準は？平仮名カタカナで単純に切ってる感じでもない→ https://github.com/unicode-org/icu/blob/master/icu4c/source/data/brkitr/dictionaries/cjdict.txt 辞書がある