Implement time range selection for TimelineOverview and TimelineRuler.

https://bugs.webkit.org/show_bug.cgi?id=126035

Reviewed by Joseph Pecoraro.

* UserInterface/TimelineContentView.js:
(WebInspector.TimelineContentView.prototype._update):
(WebInspector.TimelineContentView.prototype._recordingReset):
Properly update start time and the selection start time on reset.

* UserInterface/TimelineOverview.js:
(WebInspector.TimelineOverview):
(WebInspector.TimelineOverview.prototype.get selectionStartTime):
(WebInspector.TimelineOverview.prototype.set selectionStartTime):
(WebInspector.TimelineOverview.prototype.get selectionDuration):
(WebInspector.TimelineOverview.prototype.set selectionDuration):
Added selection getters and setters.

* UserInterface/TimelineRuler.css:
(.timeline-ruler.allows-time-range-selection):
(.timeline-ruler > *):
(.timeline-ruler > .header):
(.timeline-ruler > .selection-drag):
(.timeline-ruler > .selection-drag:active):
(.timeline-ruler > .selection-handle):
(.timeline-ruler > .selection-handle.left):
(.timeline-ruler > .selection-handle.right):
(.timeline-ruler > .shaded-area):
(.timeline-ruler > .shaded-area.left):
(.timeline-ruler > .shaded-area.right):
Added styles for the selection elements and tweaked pointer-events to allow
events on elements we expect.

* UserInterface/TimelineRuler.js:
(WebInspector.TimelineRuler):
(WebInspector.TimelineRuler.prototype.get allowsTimeRangeSelection): Added.
(WebInspector.TimelineRuler.prototype.set allowsTimeRangeSelection): Added.
(WebInspector.TimelineRuler.prototype.get selectionStartTime): Added.
(WebInspector.TimelineRuler.prototype.set selectionStartTime): Added.
(WebInspector.TimelineRuler.prototype.get selectionEndTime): Added.
(WebInspector.TimelineRuler.prototype.set selectionEndTime): Added.
(WebInspector.TimelineRuler.prototype.updateLayout):
(WebInspector.TimelineRuler.prototype._needsMarkerLayout.update):
(WebInspector.TimelineRuler.prototype._needsMarkerLayout):
(WebInspector.TimelineRuler.prototype._needsSelectionLayout.update):
(WebInspector.TimelineRuler.prototype._needsSelectionLayout):
(WebInspector.TimelineRuler.prototype._recalculate):
(WebInspector.TimelineRuler.prototype._updatePositionOfElement):
(WebInspector.TimelineRuler.prototype._updateMarkers):
(WebInspector.TimelineRuler.prototype._updateSelection): Added.
(WebInspector.TimelineRuler.prototype._dispatchTimeRangeSelectionChangedEvent):
(WebInspector.TimelineRuler.prototype._timelineMarkerTimeChanged):
(WebInspector.TimelineRuler.prototype._handleMouseDown): Added.
(WebInspector.TimelineRuler.prototype._handleMouseMove): Added.
(WebInspector.TimelineRuler.prototype._handleMouseUp): Added.
(WebInspector.TimelineRuler.prototype._handleSelectionHandleMouseDown): Added.
(WebInspector.TimelineRuler.prototype._handleSelectionHandleMouseMove): Added.
(WebInspector.TimelineRuler.prototype._handleSelectionHandleMouseUp): Added.
Create selection elements and handle mouse events for drag and move.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@162410 268f45cc-cd09-0410-ab3c-d52691b4dbfc