When the viewport width is changed text wrapping of korean characters is not accurate. This is mainly found when there is a tag inside a tag for e.g. <div>----<span>---</span>----</div> i.e. span inside a div tag.This issue is only for few languages like chinese or korean but is working fine with english.
The improper line break is causing this issue which can be found in RenderBlockLineLayout.cpp under the function findnextlinebreak. I have added the snapshot for the reference.
Created attachment 123583 [details]
Snaphot showing the issue : eventhough there is space on the right hand side of the first line , line breaks and character comes down.
Snaphot showing the issue.
Created attachment 123584 [details]
snapshot showing the normal behavior when there is only 1tag and no tag inside a tag.