Don't display pie chart when event is not a parent.

Relanding of https://codereview.chromium.org/718283002/ that was
reverted with 769183002 due to closure compiler errors.

No drive-by CSS fix. :)

BUG=421295

Review URL: https://codereview.chromium.org/770323003

git-svn-id: svn://svn.chromium.org/blink/trunk@186389 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[DevTools] Console view should hide the suggestion box upon console clear (Ctrl/Cmd+L).

This CL hides the suggestion box shown on the console prompt. When the developer has typed a character on the
prompt (the prompt is somewhere down the viewport) and he presses Ctrl/Cmd+L to clear the console, the suggestion
box stays in skewed manner.

R=pfeldman@chromium.org

Review URL: https://codereview.chromium.org/773883003

git-svn-id: svn://svn.chromium.org/blink/trunk@186391 bbb929c8-8fbe-4397-9dbb-9b2b20218538