Improve collapsing of TimelineDataGridNode graphs up to ancestors.

https://bugs.webkit.org/show_bug.cgi?id=127440

Reviewed by Joseph Pecoraro.

* UserInterface/TimelineDataGridNode.js:
(WebInspector.TimelineDataGridNode.prototype.collapse):
(WebInspector.TimelineDataGridNode.prototype.createCellContent):
(WebInspector.TimelineDataGridNode.prototype.refresh):
(WebInspector.TimelineDataGridNode.prototype.needsGraphRefresh):
Notify the next visible ancestor it needs to refresh. Use needsGraphRefresh so ancestors
are notified instead of directly calling refreshGraph in some places.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@162564 268f45cc-cd09-0410-ab3c-d52691b4dbfc