Add statusbar with checkboxes to Layers3DView.

Review URL: https://codereview.chromium.org/371943002

Review URL: https://codereview.chromium.org/371943002

git-svn-id: svn://svn.chromium.org/blink/trunk@177652 bbb929c8-8fbe-4397-9dbb-9b2b20218538