DevTools: Fix overflow counting in console preview.

This fixes "console.log({a:1, b:2, c:3, d:4, e:5});" being shown with overflow style in console.

R=pfeldman

Review URL: https://codereview.chromium.org/83723003

git-svn-id: svn://svn.chromium.org/blink/trunk@162699 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Revert "Put RuleSets on their StyleSheetContents."

This reverts r162573. It may have caused some perf regressions.

BUG=323370
TBR=esprehn@chromium.org

Review URL: https://codereview.chromium.org/88423003

git-svn-id: svn://svn.chromium.org/blink/trunk@162700 bbb929c8-8fbe-4397-9dbb-9b2b20218538