[DevTools] Scale canvas steps on responsive design view.

BUG=327641

Review URL: https://codereview.chromium.org/355433002

git-svn-id: svn://svn.chromium.org/blink/trunk@176760 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Color paint profiler bars.

Review URL: https://codereview.chromium.org/340363004

git-svn-id: svn://svn.chromium.org/blink/trunk@176761 bbb929c8-8fbe-4397-9dbb-9b2b20218538