DevTools: Make console animation faster and cleaner, especially on the sources panel.

Console animation time is reduced down to 100ms.
Animation is performed using requestAnimaitonFrame now, not setInterval.
CodeMirrorTextEditor is made layout boundary for better performance.
CodeMirror instance is not refreshed on resize anymore, setSize is called instead of that.
setSize method performance was improved greatly with the recent editor update.

R=pfeldman, lushnikov

Review URL: https://chromiumcodereview.appspot.com/21149006

git-svn-id: svn://svn.chromium.org/blink/trunk@155191 bbb929c8-8fbe-4397-9dbb-9b2b20218538