Web Inspector: Flame Chart. move overview window when user scrolls the chart.
https://bugs.webkit.org/show_bug.cgi?id=113014

Reviewed by Yury Semikhatsky.

I found that I could use scaling mechanics in OverviewGrid for scaling the chart.
But the dragging part was not so simple due to the different approaches in
OverviewGrid and FlameChart. OverviewGrid used _windowLeft and _windowRight
when FlameChart used _xOffset and _xScaleFactor and width.
It was not practical and I rewrote the FlameChart mechanics
and now it also uses _windowLeft _windowRight.

* inspector/front-end/FlameChart.js:
(WebInspector.FlameChart):
(WebInspector.FlameChart.Calculator.prototype._updateBoundaries):
(WebInspector.FlameChart.Calculator.prototype.computePosition):
(WebInspector.FlameChart.prototype._onWindowChanged):
(WebInspector.FlameChart.prototype._startCanvasDragging):
(WebInspector.FlameChart.prototype._canvasDragging):
(WebInspector.FlameChart.prototype._onMouseMove):
(WebInspector.FlameChart.prototype._onMouseWheel):
(WebInspector.FlameChart.prototype._coordinatesToNodeIndex):
(WebInspector.FlameChart.prototype._drawOverviewCanvas):
(WebInspector.FlameChart.prototype.draw):
(WebInspector.FlameChart.prototype._updateBoundaries):
(WebInspector.FlameChart.prototype.update):
* inspector/front-end/OverviewGrid.js:
(WebInspector.OverviewGrid.prototype.setWindowPosition):
(WebInspector.OverviewGrid.prototype.setWindow):
(WebInspector.OverviewGrid.prototype.addEventListener):
(WebInspector.OverviewGrid.prototype.zoom):
(WebInspector.OverviewGrid.Window.prototype._zoom):
* inspector/front-end/inspectorCommon.css:
(.overview-grid-window-rulers):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@146577 268f45cc-cd09-0410-ab3c-d52691b4dbfc