Improve WebInspector.TimelineOverview by not putting WebInspector.TimelineRuler in a scroll area.

https://bugs.webkit.org/show_bug.cgi?id=127145

Reviewed by Joseph Pecoraro.

* UserInterface/TimelineOverview.css:
(.timeline-overview > .scroll-container):
(.timeline-overview > .timeline-ruler):
(.timeline-overview > .scroll-container > .scroll-width-sizer):
* UserInterface/TimelineOverview.js:
(WebInspector.TimelineOverview):
(WebInspector.TimelineOverview.prototype.get startTime):
(WebInspector.TimelineOverview.prototype.set startTime):
(WebInspector.TimelineOverview.prototype.get secondsPerPixel):
(WebInspector.TimelineOverview.prototype.set secondsPerPixel):
(WebInspector.TimelineOverview.prototype.get scrollStartTime):
(WebInspector.TimelineOverview.prototype.set scrollStartTime):
(WebInspector.TimelineOverview.prototype.get visibleDuration):
(WebInspector.TimelineOverview.prototype.revealMarker):
(WebInspector.TimelineOverview.prototype.updateLayout):
(WebInspector.TimelineOverview.prototype._handleScrollEvent):
(WebInspector.TimelineOverview.prototype._handleWheelEvent):
* UserInterface/TimelineRuler.js:
(WebInspector.TimelineRuler.MinimumSelectionTimeRange): Reduce to 10ms now that super zoom has no performance impact.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@162417 268f45cc-cd09-0410-ab3c-d52691b4dbfc