Revert r160103 "Revert 160091 "DevTools: handle toolbar resize on screencast res...""

TBR=kaznacheev
BUG=

Review URL: https://codereview.chromium.org/33623003

git-svn-id: svn://svn.chromium.org/blink/trunk@160191 bbb929c8-8fbe-4397-9dbb-9b2b20218538