DevTools: Retain tabs order in sidebar tabbed panes.

BUG=267759

Review URL: https://chromiumcodereview.appspot.com/22086002

git-svn-id: svn://svn.chromium.org/blink/trunk@155484 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Fix tabbed pane measuring regression introduced after recent fonts changes.

Review URL: https://chromiumcodereview.appspot.com/22088002

git-svn-id: svn://svn.chromium.org/blink/trunk@155485 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Improve elements pseudo state pane experience

BUG=267759

Review URL: https://chromiumcodereview.appspot.com/22074003

git-svn-id: svn://svn.chromium.org/blink/trunk@155486 bbb929c8-8fbe-4397-9dbb-9b2b20218538