Revert https://src.chromium.org/viewvc/blink?view=rev&revision=183172 .

This caused a layout performance regression.  I'll be relanding it in pieces.

BUG=420103
TEST=none
TBR=jamesr

Review URL: https://codereview.chromium.org/647603002

git-svn-id: svn://svn.chromium.org/blink/trunk@183498 bbb929c8-8fbe-4397-9dbb-9b2b20218538