Filter the Timeline overview graph and sidebar based on the current time selection.

https://bugs.webkit.org/show_bug.cgi?id=126955

Reviewed by Joseph Pecoraro.

* UserInterface/NavigationSidebarPanel.js:
(WebInspector.NavigationSidebarPanel.prototype.updateFilter):
(WebInspector.NavigationSidebarPanel.prototype.hasCustomFilters):
(WebInspector.NavigationSidebarPanel.prototype.matchTreeElementAgainstCustomFilters):
(WebInspector.NavigationSidebarPanel.prototype.applyFiltersToTreeElement.matchTextFilter):
(WebInspector.NavigationSidebarPanel.prototype.applyFiltersToTreeElement):
Add support for custom filters implemented by subclasses.

* UserInterface/TimelineContentView.js:
(WebInspector.TimelineContentView.prototype.matchTreeElementAgainstCustomFilters.checkTimeBounds):
(WebInspector.TimelineContentView.prototype.matchTreeElementAgainstCustomFilters):
(WebInspector.TimelineContentView.prototype._timeRangeSelectionChanged):
Filter known tree element types by time.

* UserInterface/TimelineSidebarPanel.css:
(.sidebar > .panel.timeline > .empty-content-placeholder):
Position the empty placeholder with the content.

* UserInterface/TimelineSidebarPanel.js:
(WebInspector.TimelineSidebarPanel.prototype.hasCustomFilters):
(WebInspector.TimelineSidebarPanel.prototype.matchTreeElementAgainstCustomFilters):
Defer filtering to the TimelineContentView.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@162414 268f45cc-cd09-0410-ab3c-d52691b4dbfc