DevTools: reformat front-end code to match chromium style.

third_party/WebKit/Source/devtools/front_end/ui_lazy/OverviewGrid.js

Index: third_party/WebKit/Source/devtools/front_end/ui_lazy/OverviewGrid.js
diff --git a/third_party/WebKit/Source/devtools/front_end/ui_lazy/OverviewGrid.js b/third_party/WebKit/Source/devtools/front_end/ui_lazy/OverviewGrid.js
index 5ed402cd8d8e2b3fbcc1074018c3fe472c9ceff9..7a257d15edf4eb5c544eb99d91eaf7b8f271b1a4 100644
--- a/third_party/WebKit/Source/devtools/front_end/ui_lazy/OverviewGrid.js
+++ b/third_party/WebKit/Source/devtools/front_end/ui_lazy/OverviewGrid.js
@@ -27,440 +27,415 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
-
 /**
- * @constructor
- * @param {string} prefix
+ * @unrestricted
  */
-WebInspector.OverviewGrid = function(prefix)
-{
-    this.element = createElement("div");
-    this.element.id = prefix + "-overview-container";
+WebInspector.OverviewGrid = class {
+  /**
+   * @param {string} prefix
+   */
+  constructor(prefix) {
+    this.element = createElement('div');
+    this.element.id = prefix + '-overview-container';
 
     this._grid = new WebInspector.TimelineGrid();
-    this._grid.element.id = prefix + "-overview-grid";
+    this._grid.element.id = prefix + '-overview-grid';
     this._grid.setScrollTop(0);
 
     this.element.appendChild(this._grid.element);
 
     this._window = new WebInspector.OverviewGrid.Window(this.element, this._grid.dividersLabelBarElement);
+  }
+
+  /**
+   * @return {number}
+   */
+  clientWidth() {
+    return this.element.clientWidth;
+  }
+
+  /**
+   * @param {!WebInspector.TimelineGrid.Calculator} calculator
+   */
+  updateDividers(calculator) {
+    this._grid.updateDividers(calculator);
+  }
+
+  /**
+   * @param {!Array.<!Element>} dividers
+   */
+  addEventDividers(dividers) {
+    this._grid.addEventDividers(dividers);
+  }
+
+  removeEventDividers() {
+    this._grid.removeEventDividers();
+  }
+
+  reset() {
+    this._window.reset();
+  }
+
+  /**
+   * @return {number}
+   */
+  windowLeft() {
+    return this._window.windowLeft;
+  }
+
+  /**
+   * @return {number}
+   */
+  windowRight() {
+    return this._window.windowRight;
+  }
+
+  /**
+   * @param {number} left
+   * @param {number} right
+   */
+  setWindow(left, right) {
+    this._window._setWindow(left, right);
+  }
+
+  /**
+   * @param {string} eventType
+   * @param {function(!WebInspector.Event)} listener
+   * @param {!Object=} thisObject
+   * @return {!WebInspector.EventTarget.EventDescriptor}
+   */
+  addEventListener(eventType, listener, thisObject) {
+    return this._window.addEventListener(eventType, listener, thisObject);
+  }
+
+  /**
+   * @param {number} zoomFactor
+   * @param {number} referencePoint
+   */
+  zoom(zoomFactor, referencePoint) {
+    this._window._zoom(zoomFactor, referencePoint);
+  }
+
+  /**
+   * @param {boolean} enabled
+   */
+  setResizeEnabled(enabled) {
+    this._window.setEnabled(enabled);
+  }
 };
 
-WebInspector.OverviewGrid.prototype = {
-    /**
-     * @return {number}
-     */
-    clientWidth: function()
-    {
-        return this.element.clientWidth;
-    },
-
-    /**
-     * @param {!WebInspector.TimelineGrid.Calculator} calculator
-     */
-    updateDividers: function(calculator)
-    {
-        this._grid.updateDividers(calculator);
-    },
-
-    /**
-     * @param {!Array.<!Element>} dividers
-     */
-    addEventDividers: function(dividers)
-    {
-        this._grid.addEventDividers(dividers);
-    },
-
-    removeEventDividers: function()
-    {
-        this._grid.removeEventDividers();
-    },
-
-    reset: function()
-    {
-        this._window.reset();
-    },
-
-    /**
-     * @return {number}
-     */
-    windowLeft: function()
-    {
-        return this._window.windowLeft;
-    },
-
-    /**
-     * @return {number}
-     */
-    windowRight: function()
-    {
-        return this._window.windowRight;
-    },
-
-    /**
-     * @param {number} left
-     * @param {number} right
-     */
-    setWindow: function(left, right)
-    {
-        this._window._setWindow(left, right);
-    },
-
-    /**
-     * @param {string} eventType
-     * @param {function(!WebInspector.Event)} listener
-     * @param {!Object=} thisObject
-     * @return {!WebInspector.EventTarget.EventDescriptor}
-     */
-    addEventListener: function(eventType, listener, thisObject)
-    {
-        return this._window.addEventListener(eventType, listener, thisObject);
-    },
-
-    /**
-     * @param {number} zoomFactor
-     * @param {number} referencePoint
-     */
-    zoom: function(zoomFactor, referencePoint)
-    {
-        this._window._zoom(zoomFactor, referencePoint);
-    },
-
-    /**
-     * @param {boolean} enabled
-     */
-    setResizeEnabled: function(enabled)
-    {
-        this._window.setEnabled(enabled);
-    }
-};
-
-
 WebInspector.OverviewGrid.MinSelectableSize = 14;
 
 WebInspector.OverviewGrid.WindowScrollSpeedFactor = .3;
 
-WebInspector.OverviewGrid.ResizerOffset = 3.5; // half pixel because offset values are not rounded but ceiled
+WebInspector.OverviewGrid.ResizerOffset = 3.5;  // half pixel because offset values are not rounded but ceiled
 
 /**
- * @constructor
- * @extends {WebInspector.Object}
- * @param {!Element} parentElement
- * @param {!Element=} dividersLabelBarElement
+ * @unrestricted
  */
-WebInspector.OverviewGrid.Window = function(parentElement, dividersLabelBarElement)
-{
+WebInspector.OverviewGrid.Window = class extends WebInspector.Object {
+  /**
+   * @param {!Element} parentElement
+   * @param {!Element=} dividersLabelBarElement
+   */
+  constructor(parentElement, dividersLabelBarElement) {
+    super();
     this._parentElement = parentElement;
 
-    WebInspector.installDragHandle(this._parentElement, this._startWindowSelectorDragging.bind(this), this._windowSelectorDragging.bind(this), this._endWindowSelectorDragging.bind(this), "text", null);
+    WebInspector.installDragHandle(
+        this._parentElement, this._startWindowSelectorDragging.bind(this), this._windowSelectorDragging.bind(this),
+        this._endWindowSelectorDragging.bind(this), 'text', null);
     if (dividersLabelBarElement)
-        WebInspector.installDragHandle(dividersLabelBarElement, this._startWindowDragging.bind(this), this._windowDragging.bind(this), null, "-webkit-grabbing", "-webkit-grab");
+      WebInspector.installDragHandle(
+          dividersLabelBarElement, this._startWindowDragging.bind(this), this._windowDragging.bind(this), null,
+          '-webkit-grabbing', '-webkit-grab');
+
+    this._parentElement.addEventListener('mousewheel', this._onMouseWheel.bind(this), true);
+    this._parentElement.addEventListener('dblclick', this._resizeWindowMaximum.bind(this), true);
+    WebInspector.appendStyle(this._parentElement, 'ui_lazy/overviewGrid.css');
+
+    this._leftResizeElement = parentElement.createChild('div', 'overview-grid-window-resizer');
+    WebInspector.installDragHandle(
+        this._leftResizeElement, this._resizerElementStartDragging.bind(this),
+        this._leftResizeElementDragging.bind(this), null, 'ew-resize');
+    this._rightResizeElement = parentElement.createChild('div', 'overview-grid-window-resizer');
+    WebInspector.installDragHandle(
+        this._rightResizeElement, this._resizerElementStartDragging.bind(this),
+        this._rightResizeElementDragging.bind(this), null, 'ew-resize');
+
+    this._leftCurtainElement = parentElement.createChild('div', 'window-curtain-left');
+    this._rightCurtainElement = parentElement.createChild('div', 'window-curtain-right');
+    this.reset();
+  }
+
+  reset() {
+    this.windowLeft = 0.0;
+    this.windowRight = 1.0;
+    this.setEnabled(true);
+    this._updateCurtains();
+  }
+
+  /**
+   * @param {boolean} enabled
+   */
+  setEnabled(enabled) {
+    this._enabled = enabled;
+  }
+
+  /**
+   * @param {!Event} event
+   */
+  _resizerElementStartDragging(event) {
+    if (!this._enabled)
+      return false;
+    this._resizerParentOffsetLeft = event.pageX - event.offsetX - event.target.offsetLeft;
+    event.preventDefault();
+    return true;
+  }
+
+  /**
+   * @param {!Event} event
+   */
+  _leftResizeElementDragging(event) {
+    this._resizeWindowLeft(event.pageX - this._resizerParentOffsetLeft);
+    event.preventDefault();
+  }
+
+  /**
+   * @param {!Event} event
+   */
+  _rightResizeElementDragging(event) {
+    this._resizeWindowRight(event.pageX - this._resizerParentOffsetLeft);
+    event.preventDefault();
+  }
+
+  /**
+   * @param {!Event} event
+   * @return {boolean}
+   */
+  _startWindowSelectorDragging(event) {
+    if (!this._enabled)
+      return false;
+    this._offsetLeft = this._parentElement.totalOffsetLeft();
+    var position = event.x - this._offsetLeft;
+    this._overviewWindowSelector = new WebInspector.OverviewGrid.WindowSelector(this._parentElement, position);
+    return true;
+  }
+
+  /**
+   * @param {!Event} event
+   */
+  _windowSelectorDragging(event) {
+    this._overviewWindowSelector._updatePosition(event.x - this._offsetLeft);
+    event.preventDefault();
+  }
+
+  /**
+   * @param {!Event} event
+   */
+  _endWindowSelectorDragging(event) {
+    var window = this._overviewWindowSelector._close(event.x - this._offsetLeft);
+    delete this._overviewWindowSelector;
+    var clickThreshold = 3;
+    if (window.end - window.start < clickThreshold) {
+      if (this.dispatchEventToListeners(WebInspector.OverviewGrid.Events.Click, event))
+        return;
+      var middle = window.end;
+      window.start = Math.max(0, middle - WebInspector.OverviewGrid.MinSelectableSize / 2);
+      window.end = Math.min(this._parentElement.clientWidth, middle + WebInspector.OverviewGrid.MinSelectableSize / 2);
+    } else if (window.end - window.start < WebInspector.OverviewGrid.MinSelectableSize) {
+      if (this._parentElement.clientWidth - window.end > WebInspector.OverviewGrid.MinSelectableSize)
+        window.end = window.start + WebInspector.OverviewGrid.MinSelectableSize;
+      else
+        window.start = window.end - WebInspector.OverviewGrid.MinSelectableSize;
+    }
+    this._setWindowPosition(window.start, window.end);
+  }
+
+  /**
+   * @param {!Event} event
+   * @return {boolean}
+   */
+  _startWindowDragging(event) {
+    this._dragStartPoint = event.pageX;
+    this._dragStartLeft = this.windowLeft;
+    this._dragStartRight = this.windowRight;
+    event.stopPropagation();
+    return true;
+  }
+
+  /**
+   * @param {!Event} event
+   */
+  _windowDragging(event) {
+    event.preventDefault();
+    var delta = (event.pageX - this._dragStartPoint) / this._parentElement.clientWidth;
+    if (this._dragStartLeft + delta < 0)
+      delta = -this._dragStartLeft;
+
+    if (this._dragStartRight + delta > 1)
+      delta = 1 - this._dragStartRight;
+
+    this._setWindow(this._dragStartLeft + delta, this._dragStartRight + delta);
+  }
+
+  /**
+   * @param {number} start
+   */
+  _resizeWindowLeft(start) {
+    // Glue to edge.
+    if (start < 10)
+      start = 0;
+    else if (start > this._rightResizeElement.offsetLeft - 4)
+      start = this._rightResizeElement.offsetLeft - 4;
+    this._setWindowPosition(start, null);
+  }
+
+  /**
+   * @param {number} end
+   */
+  _resizeWindowRight(end) {
+    // Glue to edge.
+    if (end > this._parentElement.clientWidth - 10)
+      end = this._parentElement.clientWidth;
+    else if (end < this._leftResizeElement.offsetLeft + WebInspector.OverviewGrid.MinSelectableSize)
+      end = this._leftResizeElement.offsetLeft + WebInspector.OverviewGrid.MinSelectableSize;
+    this._setWindowPosition(null, end);
+  }
+
+  _resizeWindowMaximum() {
+    this._setWindowPosition(0, this._parentElement.clientWidth);
+  }
+
+  /**
+   * @param {number} windowLeft
+   * @param {number} windowRight
+   */
+  _setWindow(windowLeft, windowRight) {
+    this.windowLeft = windowLeft;
+    this.windowRight = windowRight;
+    this._updateCurtains();
+    this.dispatchEventToListeners(WebInspector.OverviewGrid.Events.WindowChanged);
+  }
+
+  _updateCurtains() {
+    var left = this.windowLeft;
+    var right = this.windowRight;
+    var width = right - left;
+
+    // We allow actual time window to be arbitrarily small but don't want the UI window to be too small.
+    var widthInPixels = width * this._parentElement.clientWidth;
+    var minWidthInPixels = WebInspector.OverviewGrid.MinSelectableSize / 2;
+    if (widthInPixels < minWidthInPixels) {
+      var factor = minWidthInPixels / widthInPixels;
+      left = ((this.windowRight + this.windowLeft) - width * factor) / 2;
+      right = ((this.windowRight + this.windowLeft) + width * factor) / 2;
+    }
+    this._leftResizeElement.style.left = (100 * left).toFixed(2) + '%';
+    this._rightResizeElement.style.left = (100 * right).toFixed(2) + '%';
+
+    this._leftCurtainElement.style.width = (100 * left).toFixed(2) + '%';
+    this._rightCurtainElement.style.width = (100 * (1 - right)).toFixed(2) + '%';
+  }
+
+  /**
+   * @param {?number} start
+   * @param {?number} end
+   */
+  _setWindowPosition(start, end) {
+    var clientWidth = this._parentElement.clientWidth;
+    var windowLeft = typeof start === 'number' ? start / clientWidth : this.windowLeft;
+    var windowRight = typeof end === 'number' ? end / clientWidth : this.windowRight;
+    this._setWindow(windowLeft, windowRight);
+  }
+
+  /**
+   * @param {!Event} event
+   */
+  _onMouseWheel(event) {
+    if (!this._enabled)
+      return;
+    if (typeof event.wheelDeltaY === 'number' && event.wheelDeltaY) {
+      const zoomFactor = 1.1;
+      const mouseWheelZoomSpeed = 1 / 120;
+
+      var reference = event.offsetX / event.target.clientWidth;
+      this._zoom(Math.pow(zoomFactor, -event.wheelDeltaY * mouseWheelZoomSpeed), reference);
+    }
+    if (typeof event.wheelDeltaX === 'number' && event.wheelDeltaX) {
+      var offset = Math.round(event.wheelDeltaX * WebInspector.OverviewGrid.WindowScrollSpeedFactor);
+      var windowLeft = this._leftResizeElement.offsetLeft + WebInspector.OverviewGrid.ResizerOffset;
+      var windowRight = this._rightResizeElement.offsetLeft + WebInspector.OverviewGrid.ResizerOffset;
 
-    this._parentElement.addEventListener("mousewheel", this._onMouseWheel.bind(this), true);
-    this._parentElement.addEventListener("dblclick", this._resizeWindowMaximum.bind(this), true);
-    WebInspector.appendStyle(this._parentElement, "ui_lazy/overviewGrid.css");
+      if (windowLeft - offset < 0)
+        offset = windowLeft;
 
-    this._leftResizeElement = parentElement.createChild("div", "overview-grid-window-resizer");
-    WebInspector.installDragHandle(this._leftResizeElement, this._resizerElementStartDragging.bind(this), this._leftResizeElementDragging.bind(this), null, "ew-resize");
-    this._rightResizeElement = parentElement.createChild("div", "overview-grid-window-resizer");
-    WebInspector.installDragHandle(this._rightResizeElement, this._resizerElementStartDragging.bind(this), this._rightResizeElementDragging.bind(this), null, "ew-resize");
+      if (windowRight - offset > this._parentElement.clientWidth)
+        offset = windowRight - this._parentElement.clientWidth;
 
-    this._leftCurtainElement = parentElement.createChild("div", "window-curtain-left");
-    this._rightCurtainElement = parentElement.createChild("div", "window-curtain-right");
-    this.reset();
+      this._setWindowPosition(windowLeft - offset, windowRight - offset);
+
+      event.preventDefault();
+    }
+  }
+
+  /**
+   * @param {number} factor
+   * @param {number} reference
+   */
+  _zoom(factor, reference) {
+    var left = this.windowLeft;
+    var right = this.windowRight;
+    var windowSize = right - left;
+    var newWindowSize = factor * windowSize;
+    if (newWindowSize > 1) {
+      newWindowSize = 1;
+      factor = newWindowSize / windowSize;
+    }
+    left = reference + (left - reference) * factor;
+    left = Number.constrain(left, 0, 1 - newWindowSize);
+
+    right = reference + (right - reference) * factor;
+    right = Number.constrain(right, newWindowSize, 1);
+    this._setWindow(left, right);
+  }
 };
 
 /** @enum {symbol} */
 WebInspector.OverviewGrid.Events = {
-    WindowChanged: Symbol("WindowChanged"),
-    Click: Symbol("Click")
-};
-
-WebInspector.OverviewGrid.Window.prototype = {
-    reset: function()
-    {
-        this.windowLeft = 0.0;
-        this.windowRight = 1.0;
-        this.setEnabled(true);
-        this._updateCurtains();
-    },
-
-    /**
-     * @param {boolean} enabled
-     */
-    setEnabled: function(enabled)
-    {
-        this._enabled = enabled;
-    },
-
-    /**
-     * @param {!Event} event
-     */
-    _resizerElementStartDragging: function(event)
-    {
-        if (!this._enabled)
-            return false;
-        this._resizerParentOffsetLeft = event.pageX - event.offsetX - event.target.offsetLeft;
-        event.preventDefault();
-        return true;
-    },
-
-    /**
-     * @param {!Event} event
-     */
-    _leftResizeElementDragging: function(event)
-    {
-        this._resizeWindowLeft(event.pageX - this._resizerParentOffsetLeft);
-        event.preventDefault();
-    },
-
-    /**
-     * @param {!Event} event
-     */
-    _rightResizeElementDragging: function(event)
-    {
-        this._resizeWindowRight(event.pageX - this._resizerParentOffsetLeft);
-        event.preventDefault();
-    },
-
-    /**
-     * @param {!Event} event
-     * @return {boolean}
-     */
-    _startWindowSelectorDragging: function(event)
-    {
-        if (!this._enabled)
-            return false;
-        this._offsetLeft = this._parentElement.totalOffsetLeft();
-        var position = event.x - this._offsetLeft;
-        this._overviewWindowSelector = new WebInspector.OverviewGrid.WindowSelector(this._parentElement, position);
-        return true;
-    },
-
-    /**
-     * @param {!Event} event
-     */
-    _windowSelectorDragging: function(event)
-    {
-        this._overviewWindowSelector._updatePosition(event.x - this._offsetLeft);
-        event.preventDefault();
-    },
-
-    /**
-     * @param {!Event} event
-     */
-    _endWindowSelectorDragging: function(event)
-    {
-        var window = this._overviewWindowSelector._close(event.x - this._offsetLeft);
-        delete this._overviewWindowSelector;
-        var clickThreshold = 3;
-        if (window.end - window.start < clickThreshold) {
-            if (this.dispatchEventToListeners(WebInspector.OverviewGrid.Events.Click, event))
-                return;
-            var middle = window.end;
-            window.start = Math.max(0, middle - WebInspector.OverviewGrid.MinSelectableSize / 2);
-            window.end = Math.min(this._parentElement.clientWidth, middle + WebInspector.OverviewGrid.MinSelectableSize / 2);
-        } else if (window.end - window.start < WebInspector.OverviewGrid.MinSelectableSize) {
-            if (this._parentElement.clientWidth - window.end > WebInspector.OverviewGrid.MinSelectableSize)
-                window.end = window.start + WebInspector.OverviewGrid.MinSelectableSize;
-            else
-                window.start = window.end - WebInspector.OverviewGrid.MinSelectableSize;
-        }
-        this._setWindowPosition(window.start, window.end);
-    },
-
-    /**
-     * @param {!Event} event
-     * @return {boolean}
-     */
-    _startWindowDragging: function(event)
-    {
-        this._dragStartPoint = event.pageX;
-        this._dragStartLeft = this.windowLeft;
-        this._dragStartRight = this.windowRight;
-        event.stopPropagation();
-        return true;
-    },
-
-    /**
-     * @param {!Event} event
-     */
-    _windowDragging: function(event)
-    {
-        event.preventDefault();
-        var delta = (event.pageX - this._dragStartPoint) / this._parentElement.clientWidth;
-        if (this._dragStartLeft + delta < 0)
-            delta = -this._dragStartLeft;
-
-        if (this._dragStartRight + delta > 1)
-            delta = 1 - this._dragStartRight;
-
-        this._setWindow(this._dragStartLeft + delta, this._dragStartRight + delta);
-    },
-
-    /**
-     * @param {number} start
-     */
-    _resizeWindowLeft: function(start)
-    {
-        // Glue to edge.
-        if (start < 10)
-            start = 0;
-        else if (start > this._rightResizeElement.offsetLeft -  4)
-            start = this._rightResizeElement.offsetLeft - 4;
-        this._setWindowPosition(start, null);
-    },
-
-    /**
-     * @param {number} end
-     */
-    _resizeWindowRight: function(end)
-    {
-        // Glue to edge.
-        if (end > this._parentElement.clientWidth - 10)
-            end = this._parentElement.clientWidth;
-        else if (end < this._leftResizeElement.offsetLeft + WebInspector.OverviewGrid.MinSelectableSize)
-            end = this._leftResizeElement.offsetLeft + WebInspector.OverviewGrid.MinSelectableSize;
-        this._setWindowPosition(null, end);
-    },
-
-    _resizeWindowMaximum: function()
-    {
-        this._setWindowPosition(0, this._parentElement.clientWidth);
-    },
-
-    /**
-     * @param {number} windowLeft
-     * @param {number} windowRight
-     */
-    _setWindow: function(windowLeft, windowRight)
-    {
-        this.windowLeft = windowLeft;
-        this.windowRight = windowRight;
-        this._updateCurtains();
-        this.dispatchEventToListeners(WebInspector.OverviewGrid.Events.WindowChanged);
-    },
-
-    _updateCurtains: function()
-    {
-        var left = this.windowLeft;
-        var right = this.windowRight;
-        var width = right - left;
-
-        // We allow actual time window to be arbitrarily small but don't want the UI window to be too small.
-        var widthInPixels = width * this._parentElement.clientWidth;
-        var minWidthInPixels = WebInspector.OverviewGrid.MinSelectableSize / 2;
-        if (widthInPixels < minWidthInPixels) {
-            var factor = minWidthInPixels / widthInPixels;
-            left = ((this.windowRight + this.windowLeft) - width * factor) / 2;
-            right = ((this.windowRight + this.windowLeft) + width * factor) / 2;
-        }
-        this._leftResizeElement.style.left = (100 * left).toFixed(2) + "%";
-        this._rightResizeElement.style.left = (100 * right).toFixed(2) + "%";
-
-        this._leftCurtainElement.style.width = (100 * left).toFixed(2) + "%";
-        this._rightCurtainElement.style.width = (100 * (1 - right)).toFixed(2) + "%";
-    },
-
-    /**
-     * @param {?number} start
-     * @param {?number} end
-     */
-    _setWindowPosition: function(start, end)
-    {
-        var clientWidth = this._parentElement.clientWidth;
-        var windowLeft = typeof start === "number" ? start / clientWidth : this.windowLeft;
-        var windowRight = typeof end === "number" ? end / clientWidth : this.windowRight;
-        this._setWindow(windowLeft, windowRight);
-    },
-
-    /**
-     * @param {!Event} event
-     */
-    _onMouseWheel: function(event)
-    {
-        if (!this._enabled)
-            return;
-        if (typeof event.wheelDeltaY === "number" && event.wheelDeltaY) {
-            const zoomFactor = 1.1;
-            const mouseWheelZoomSpeed = 1 / 120;
-
-            var reference = event.offsetX / event.target.clientWidth;
-            this._zoom(Math.pow(zoomFactor, -event.wheelDeltaY * mouseWheelZoomSpeed), reference);
-        }
-        if (typeof event.wheelDeltaX === "number" && event.wheelDeltaX) {
-            var offset = Math.round(event.wheelDeltaX * WebInspector.OverviewGrid.WindowScrollSpeedFactor);
-            var windowLeft = this._leftResizeElement.offsetLeft + WebInspector.OverviewGrid.ResizerOffset;
-            var windowRight = this._rightResizeElement.offsetLeft + WebInspector.OverviewGrid.ResizerOffset;
-
-            if (windowLeft - offset < 0)
-                offset = windowLeft;
-
-            if (windowRight - offset > this._parentElement.clientWidth)
-                offset = windowRight - this._parentElement.clientWidth;
-
-            this._setWindowPosition(windowLeft - offset, windowRight - offset);
-
-            event.preventDefault();
-        }
-    },
-
-    /**
-     * @param {number} factor
-     * @param {number} reference
-     */
-    _zoom: function(factor, reference)
-    {
-        var left = this.windowLeft;
-        var right = this.windowRight;
-        var windowSize = right - left;
-        var newWindowSize = factor * windowSize;
-        if (newWindowSize > 1) {
-            newWindowSize = 1;
-            factor = newWindowSize / windowSize;
-        }
-        left = reference + (left - reference) * factor;
-        left = Number.constrain(left, 0, 1 - newWindowSize);
-
-        right = reference + (right - reference) * factor;
-        right = Number.constrain(right, newWindowSize, 1);
-        this._setWindow(left, right);
-    },
-
-    __proto__: WebInspector.Object.prototype
+  WindowChanged: Symbol('WindowChanged'),
+  Click: Symbol('Click')
 };
 
 /**
- * @constructor
+ * @unrestricted
  */
-WebInspector.OverviewGrid.WindowSelector = function(parent, position)
-{
+WebInspector.OverviewGrid.WindowSelector = class {
+  constructor(parent, position) {
     this._startPosition = position;
     this._width = parent.offsetWidth;
-    this._windowSelector = createElement("div");
-    this._windowSelector.className = "overview-grid-window-selector";
-    this._windowSelector.style.left = this._startPosition + "px";
-    this._windowSelector.style.right = this._width - this._startPosition + "px";
+    this._windowSelector = createElement('div');
+    this._windowSelector.className = 'overview-grid-window-selector';
+    this._windowSelector.style.left = this._startPosition + 'px';
+    this._windowSelector.style.right = this._width - this._startPosition + 'px';
     parent.appendChild(this._windowSelector);
-};
-
-WebInspector.OverviewGrid.WindowSelector.prototype = {
-    _close: function(position)
-    {
-        position = Math.max(0, Math.min(position, this._width));
-        this._windowSelector.remove();
-        return this._startPosition < position ? {start: this._startPosition, end: position} : {start: position, end: this._startPosition};
-    },
-
-    _updatePosition: function(position)
-    {
-        position = Math.max(0, Math.min(position, this._width));
-        if (position < this._startPosition) {
-            this._windowSelector.style.left = position + "px";
-            this._windowSelector.style.right = this._width - this._startPosition + "px";
-        } else {
-            this._windowSelector.style.left = this._startPosition + "px";
-            this._windowSelector.style.right = this._width - position + "px";
-        }
+  }
+
+  _close(position) {
+    position = Math.max(0, Math.min(position, this._width));
+    this._windowSelector.remove();
+    return this._startPosition < position ? {start: this._startPosition, end: position} :
+                                            {start: position, end: this._startPosition};
+  }
+
+  _updatePosition(position) {
+    position = Math.max(0, Math.min(position, this._width));
+    if (position < this._startPosition) {
+      this._windowSelector.style.left = position + 'px';
+      this._windowSelector.style.right = this._width - this._startPosition + 'px';
+    } else {
+      this._windowSelector.style.left = this._startPosition + 'px';
+      this._windowSelector.style.right = this._width - position + 'px';
     }
+  }
 };