Web Inspector: coalesce repeating timeline records
https://bugs.webkit.org/show_bug.cgi?id=112168

Reviewed by Vsevolod Vlasov.

- coalesce repeating top-level timeline events;
- drive-by: only show categories that actually took time in aggregated stats;

* English.lproj/localizedStrings.js:
* inspector/front-end/TimelineFrameController.js:
(WebInspector.TimelineFrameController.prototype._innerAddRecord):
* inspector/front-end/TimelinePanel.js:
(WebInspector.TimelinePanel.prototype._highlightRect):
(WebInspector.TimelineCalculator.prototype.computeBarGraphPercentages):
* inspector/front-end/TimelinePresentationModel.js:
(WebInspector.TimelinePresentationModel.prototype.reset):
(WebInspector.TimelinePresentationModel.prototype._innerAddRecord):
(WebInspector.TimelinePresentationModel.prototype._updateAncestorStats):
(WebInspector.TimelinePresentationModel.prototype._findCoalescedParent):
(WebInspector.TimelinePresentationModel.prototype._replaceWithCoalescedRecord):
(WebInspector.TimelinePresentationModel.Record):
(WebInspector.TimelinePresentationModel.adoptRecord):
(WebInspector.TimelinePresentationModel.insertRetrospectiveRecord):
(WebInspector.TimelinePresentationModel.Record.prototype.get selfTime):
(WebInspector.TimelinePresentationModel.Record.prototype._generatePopupContentWithImagePreview):
(WebInspector.TimelinePresentationModel.Record.prototype._getRecordDetails):
(WebInspector.TimelinePresentationModel.Record.prototype.calculateAggregatedStats):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145727 268f45cc-cd09-0410-ab3c-d52691b4dbfc