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

third_party/WebKit/Source/devtools/front_end/ui/Widget.js

Index: third_party/WebKit/Source/devtools/front_end/ui/Widget.js
diff --git a/third_party/WebKit/Source/devtools/front_end/ui/Widget.js b/third_party/WebKit/Source/devtools/front_end/ui/Widget.js
index c14e5b86aed93382997eb800be1d7ccda6e00d12..07b09d919269effa2a627cc4bf7ac01ebedd9937 100644
--- a/third_party/WebKit/Source/devtools/front_end/ui/Widget.js
+++ b/third_party/WebKit/Source/devtools/front_end/ui/Widget.js
@@ -23,21 +23,22 @@
  * (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
- * @extends {WebInspector.Object}
- * @param {boolean=} isWebComponent
+ * @unrestricted
  */
-WebInspector.Widget = function(isWebComponent)
-{
-    this.contentElement = createElementWithClass("div", "widget");
+WebInspector.Widget = class extends WebInspector.Object {
+  /**
+   * @param {boolean=} isWebComponent
+   */
+  constructor(isWebComponent) {
+    super();
+    this.contentElement = createElementWithClass('div', 'widget');
     if (isWebComponent) {
-        this.element = createElementWithClass("div", "vbox flex-auto");
-        this._shadowRoot = WebInspector.createShadowRootWithCoreStyles(this.element);
-        this._shadowRoot.appendChild(this.contentElement);
+      this.element = createElementWithClass('div', 'vbox flex-auto');
+      this._shadowRoot = WebInspector.createShadowRootWithCoreStyles(this.element);
+      this._shadowRoot.appendChild(this.contentElement);
     } else {
-        this.element = this.contentElement;
+      this.element = this.contentElement;
     }
     this._isWebComponent = isWebComponent;
     this.element.__widget = this;
@@ -49,550 +50,547 @@ WebInspector.Widget = function(isWebComponent)
     this._notificationDepth = 0;
     this._invalidationsSuspended = 0;
     this._defaultFocusedChild = null;
-};
-
-WebInspector.Widget.prototype = {
-    markAsRoot: function()
-    {
-        WebInspector.Widget.__assert(!this.element.parentElement, "Attempt to mark as root attached node");
-        this._isRoot = true;
-    },
-
-    /**
-     * @return {?WebInspector.Widget}
-     */
-    parentWidget: function()
-    {
-        return this._parentWidget;
-    },
-
-    /**
-     * @return {!Array.<!WebInspector.Widget>}
-     */
-    children: function()
-    {
-        return this._children;
-    },
-
-    /**
-     * @param {!WebInspector.Widget} widget
-     * @protected
-     */
-    childWasDetached: function(widget)
-    {
-    },
-
-    /**
-     * @return {boolean}
-     */
-    isShowing: function()
-    {
-        return this._isShowing;
-    },
-
-    /**
-     * @return {boolean}
-     */
-    shouldHideOnDetach: function()
-    {
-        if (!this.element.parentElement)
-            return false;
-        if (this._hideOnDetach)
-            return true;
-        for (var child of this._children) {
-            if (child.shouldHideOnDetach())
-                return true;
-        }
-        return false;
-    },
-
-    setHideOnDetach: function()
-    {
-        this._hideOnDetach = true;
-    },
-
-    /**
-     * @return {boolean}
-     */
-    _inNotification: function()
-    {
-        return !!this._notificationDepth || (this._parentWidget && this._parentWidget._inNotification());
-    },
-
-    _parentIsShowing: function()
-    {
-        if (this._isRoot)
-            return true;
-        return !!this._parentWidget && this._parentWidget.isShowing();
-    },
-
-    /**
-     * @param {function(this:WebInspector.Widget)} method
-     */
-    _callOnVisibleChildren: function(method)
-    {
-        var copy = this._children.slice();
-        for (var i = 0; i < copy.length; ++i) {
-            if (copy[i]._parentWidget === this && copy[i]._visible)
-                method.call(copy[i]);
-        }
-    },
-
-    _processWillShow: function()
-    {
-        this._callOnVisibleChildren(this._processWillShow);
-        this._isShowing = true;
-    },
-
-    _processWasShown: function()
-    {
-        if (this._inNotification())
-            return;
-        this.restoreScrollPositions();
-        this._notify(this.wasShown);
-        this._callOnVisibleChildren(this._processWasShown);
-    },
-
-    _processWasDetachedFromHierarchy: function()
-    {
-        this._notify(this.wasDetachedFromHierarchy);
-        var copy = this._children.slice();
-        for (var widget of copy)
-            widget._processWasDetachedFromHierarchy();
-    },
-
-    _processWillHide: function()
-    {
-        if (this._inNotification())
-            return;
-        this.storeScrollPositions();
-
-        this._callOnVisibleChildren(this._processWillHide);
-        this._notify(this.willHide);
-        this._isShowing = false;
-    },
-
-    _processWasHidden: function()
-    {
-        this._callOnVisibleChildren(this._processWasHidden);
-    },
-
-    _processOnResize: function()
-    {
-        if (this._inNotification())
-            return;
-        if (!this.isShowing())
-            return;
-        this._notify(this.onResize);
-        this._callOnVisibleChildren(this._processOnResize);
-    },
-
-    /**
-     * @param {function(this:WebInspector.Widget)} notification
-     */
-    _notify: function(notification)
-    {
-        ++this._notificationDepth;
-        try {
-            notification.call(this);
-        } finally {
-            --this._notificationDepth;
-        }
-    },
-
-    wasShown: function()
-    {
-    },
-
-    willHide: function()
-    {
-    },
-
-    wasDetachedFromHierarchy: function()
-    {
-    },
-
-    onResize: function()
-    {
-    },
-
-    onLayout: function()
-    {
-    },
-
-    /**
-     * @param {!Element} parentElement
-     * @param {?Element=} insertBefore
-     */
-    show: function(parentElement, insertBefore)
-    {
-        WebInspector.Widget.__assert(parentElement, "Attempt to attach widget with no parent element");
-
-        if (!this._isRoot) {
-            // Update widget hierarchy.
-            var currentParent = parentElement;
-            while (currentParent && !currentParent.__widget)
-                currentParent = currentParent.parentElementOrShadowHost();
-            WebInspector.Widget.__assert(currentParent, "Attempt to attach widget to orphan node");
-            this.attach(currentParent.__widget);
-        }
+  }
 
-        this.showWidget(parentElement, insertBefore);
-    },
-
-    /**
-     * @param {!WebInspector.Widget} parentWidget
-     */
-    attach: function(parentWidget)
-    {
-        if (parentWidget === this._parentWidget)
-            return;
-        if (this._parentWidget)
-            this.detach();
-        this._parentWidget = parentWidget;
-        this._parentWidget._children.push(this);
-        this._isRoot = false;
-    },
-
-    /**
-     * @param {!Element} parentElement
-     * @param {?Element=} insertBefore
-     */
-    showWidget: function(parentElement, insertBefore)
-    {
-        var currentParent = parentElement;
-        while (currentParent && !currentParent.__widget)
-            currentParent = currentParent.parentElementOrShadowHost();
-
-        if (this._isRoot)
-            WebInspector.Widget.__assert(!currentParent, "Attempt to show root widget under another widget");
-        else
-            WebInspector.Widget.__assert(currentParent && currentParent.__widget === this._parentWidget, "Attempt to show under node belonging to alien widget");
-
-        var wasVisible = this._visible;
-        if (wasVisible && this.element.parentElement === parentElement)
-            return;
-
-        this._visible = true;
-
-        if (!wasVisible && this._parentIsShowing())
-            this._processWillShow();
-
-        this.element.classList.remove("hidden");
-
-        // Reparent
-        if (this.element.parentElement !== parentElement) {
-            WebInspector.Widget._incrementWidgetCounter(parentElement, this.element);
-            if (insertBefore)
-                WebInspector.Widget._originalInsertBefore.call(parentElement, this.element, insertBefore);
-            else
-                WebInspector.Widget._originalAppendChild.call(parentElement, this.element);
-        }
-
-        if (!wasVisible && this._parentIsShowing())
-            this._processWasShown();
-
-        if (this._parentWidget && this._hasNonZeroConstraints())
-            this._parentWidget.invalidateConstraints();
-        else
-            this._processOnResize();
-    },
-
-    hideWidget: function()
-    {
-        if (!this._parentWidget)
-            return;
-        this._hideWidget();
-    },
-
-    /**
-     * @param {boolean=} overrideHideOnDetach
-     */
-    _hideWidget: function(overrideHideOnDetach)
-    {
-        if (!this._visible)
-            return;
-        this._visible = false;
-        var parentElement = this.element.parentElement;
-
-        if (this._parentIsShowing())
-            this._processWillHide();
-
-        if (!overrideHideOnDetach && this.shouldHideOnDetach()) {
-            this.element.classList.add("hidden");
-        } else {
-            // Force legal removal
-            WebInspector.Widget._decrementWidgetCounter(parentElement, this.element);
-            WebInspector.Widget._originalRemoveChild.call(parentElement, this.element);
-        }
+  static _incrementWidgetCounter(parentElement, childElement) {
+    var count = (childElement.__widgetCounter || 0) + (childElement.__widget ? 1 : 0);
+    if (!count)
+      return;
 
-        if (this._parentIsShowing())
-            this._processWasHidden();
-        if (this._parentWidget && this._hasNonZeroConstraints())
-            this._parentWidget.invalidateConstraints();
-    },
-
-    detach: function()
-    {
-        if (!this._parentWidget && !this._isRoot)
-            return;
-
-        if (this._visible)
-            this._hideWidget(true);
-
-        // Update widget hierarchy.
-        if (this._parentWidget) {
-            var childIndex = this._parentWidget._children.indexOf(this);
-            WebInspector.Widget.__assert(childIndex >= 0, "Attempt to remove non-child widget");
-            this._parentWidget._children.splice(childIndex, 1);
-            if (this._parentWidget._defaultFocusedChild === this)
-                this._parentWidget._defaultFocusedChild = null;
-            this._parentWidget.childWasDetached(this);
-            var parent = this._parentWidget;
-            this._parentWidget = null;
-            this._processWasDetachedFromHierarchy();
-        } else {
-            WebInspector.Widget.__assert(this._isRoot, "Removing non-root widget from DOM");
-        }
-    },
+    while (parentElement) {
+      parentElement.__widgetCounter = (parentElement.__widgetCounter || 0) + count;
+      parentElement = parentElement.parentElementOrShadowHost();
+    }
+  }
 
-    detachChildWidgets: function()
-    {
-        var children = this._children.slice();
-        for (var i = 0; i < children.length; ++i)
-            children[i].detach();
-    },
+  static _decrementWidgetCounter(parentElement, childElement) {
+    var count = (childElement.__widgetCounter || 0) + (childElement.__widget ? 1 : 0);
+    if (!count)
+      return;
 
-    /**
-     * @return {!Array.<!Element>}
-     */
-    elementsToRestoreScrollPositionsFor: function()
-    {
-        return [this.element];
-    },
-
-    storeScrollPositions: function()
-    {
-        var elements = this.elementsToRestoreScrollPositionsFor();
-        for (var i = 0; i < elements.length; ++i) {
-            var container = elements[i];
-            container._scrollTop = container.scrollTop;
-            container._scrollLeft = container.scrollLeft;
-        }
-    },
-
-    restoreScrollPositions: function()
-    {
-        var elements = this.elementsToRestoreScrollPositionsFor();
-        for (var i = 0; i < elements.length; ++i) {
-            var container = elements[i];
-            if (container._scrollTop)
-                container.scrollTop = container._scrollTop;
-            if (container._scrollLeft)
-                container.scrollLeft = container._scrollLeft;
-        }
-    },
-
-    doResize: function()
-    {
-        if (!this.isShowing())
-            return;
-        // No matter what notification we are in, dispatching onResize is not needed.
-        if (!this._inNotification())
-            this._callOnVisibleChildren(this._processOnResize);
-    },
-
-    doLayout: function()
-    {
-        if (!this.isShowing())
-            return;
-        this._notify(this.onLayout);
-        this.doResize();
-    },
+    while (parentElement) {
+      parentElement.__widgetCounter -= count;
+      parentElement = parentElement.parentElementOrShadowHost();
+    }
+  }
 
-    /**
-     * @param {string} cssFile
-     */
-    registerRequiredCSS: function(cssFile)
-    {
-        WebInspector.appendStyle(this._isWebComponent ? this._shadowRoot : this.element, cssFile);
-    },
+  static __assert(condition, message) {
+    if (!condition) {
+      console.trace();
+      throw new Error(message);
+    }
+  }
 
-    printWidgetHierarchy: function()
-    {
-        var lines = [];
-        this._collectWidgetHierarchy("", lines);
-        console.log(lines.join("\n"));
-    },
+  /**
+   * @param {?Node} node
+   */
+  static focusWidgetForNode(node) {
+    while (node) {
+      if (node.__widget)
+        break;
+      node = node.parentNodeOrShadowHost();
+    }
+    if (!node)
+      return;
 
-    _collectWidgetHierarchy: function(prefix, lines)
-    {
-        lines.push(prefix + "[" + this.element.className + "]" + (this._children.length ? " {" : ""));
+    var widget = node.__widget;
+    while (widget._parentWidget) {
+      widget._parentWidget._defaultFocusedChild = widget;
+      widget = widget._parentWidget;
+    }
+  }
+
+  markAsRoot() {
+    WebInspector.Widget.__assert(!this.element.parentElement, 'Attempt to mark as root attached node');
+    this._isRoot = true;
+  }
+
+  /**
+   * @return {?WebInspector.Widget}
+   */
+  parentWidget() {
+    return this._parentWidget;
+  }
+
+  /**
+   * @return {!Array.<!WebInspector.Widget>}
+   */
+  children() {
+    return this._children;
+  }
+
+  /**
+   * @param {!WebInspector.Widget} widget
+   * @protected
+   */
+  childWasDetached(widget) {
+  }
+
+  /**
+   * @return {boolean}
+   */
+  isShowing() {
+    return this._isShowing;
+  }
+
+  /**
+   * @return {boolean}
+   */
+  shouldHideOnDetach() {
+    if (!this.element.parentElement)
+      return false;
+    if (this._hideOnDetach)
+      return true;
+    for (var child of this._children) {
+      if (child.shouldHideOnDetach())
+        return true;
+    }
+    return false;
+  }
+
+  setHideOnDetach() {
+    this._hideOnDetach = true;
+  }
+
+  /**
+   * @return {boolean}
+   */
+  _inNotification() {
+    return !!this._notificationDepth || (this._parentWidget && this._parentWidget._inNotification());
+  }
+
+  _parentIsShowing() {
+    if (this._isRoot)
+      return true;
+    return !!this._parentWidget && this._parentWidget.isShowing();
+  }
+
+  /**
+   * @param {function(this:WebInspector.Widget)} method
+   */
+  _callOnVisibleChildren(method) {
+    var copy = this._children.slice();
+    for (var i = 0; i < copy.length; ++i) {
+      if (copy[i]._parentWidget === this && copy[i]._visible)
+        method.call(copy[i]);
+    }
+  }
+
+  _processWillShow() {
+    this._callOnVisibleChildren(this._processWillShow);
+    this._isShowing = true;
+  }
+
+  _processWasShown() {
+    if (this._inNotification())
+      return;
+    this.restoreScrollPositions();
+    this._notify(this.wasShown);
+    this._callOnVisibleChildren(this._processWasShown);
+  }
+
+  _processWasDetachedFromHierarchy() {
+    this._notify(this.wasDetachedFromHierarchy);
+    var copy = this._children.slice();
+    for (var widget of copy)
+      widget._processWasDetachedFromHierarchy();
+  }
+
+  _processWillHide() {
+    if (this._inNotification())
+      return;
+    this.storeScrollPositions();
+
+    this._callOnVisibleChildren(this._processWillHide);
+    this._notify(this.willHide);
+    this._isShowing = false;
+  }
+
+  _processWasHidden() {
+    this._callOnVisibleChildren(this._processWasHidden);
+  }
+
+  _processOnResize() {
+    if (this._inNotification())
+      return;
+    if (!this.isShowing())
+      return;
+    this._notify(this.onResize);
+    this._callOnVisibleChildren(this._processOnResize);
+  }
+
+  /**
+   * @param {function(this:WebInspector.Widget)} notification
+   */
+  _notify(notification) {
+    ++this._notificationDepth;
+    try {
+      notification.call(this);
+    } finally {
+      --this._notificationDepth;
+    }
+  }
 
-        for (var i = 0; i < this._children.length; ++i)
-            this._children[i]._collectWidgetHierarchy(prefix + "    ", lines);
+  wasShown() {
+  }
 
-        if (this._children.length)
-            lines.push(prefix + "}");
-    },
+  willHide() {
+  }
 
-    /**
-     * @param {?Element} element
-     */
-    setDefaultFocusedElement: function(element)
-    {
-        this._defaultFocusedElement = element;
-    },
+  wasDetachedFromHierarchy() {
+  }
 
-    /**
-     * @param {!WebInspector.Widget} child
-     */
-    setDefaultFocusedChild: function(child)
-    {
-        WebInspector.Widget.__assert(child._parentWidget === this, "Attempt to set non-child widget as default focused.");
-        this._defaultFocusedChild = child;
-    },
-
-    focus: function()
-    {
-        if (!this.isShowing())
-            return;
-
-        var element = this._defaultFocusedElement;
-        if (element) {
-            if (!element.hasFocus())
-                element.focus();
-            return;
-        }
+  onResize() {
+  }
 
-        if (this._defaultFocusedChild && this._defaultFocusedChild._visible) {
-            this._defaultFocusedChild.focus();
-        } else {
-            for (var child of this._children) {
-                if (child._visible) {
-                    child.focus();
-                    break;
-                }
-            }
-        }
+  onLayout() {
+  }
 
-    },
+  /**
+   * @param {!Element} parentElement
+   * @param {?Element=} insertBefore
+   */
+  show(parentElement, insertBefore) {
+    WebInspector.Widget.__assert(parentElement, 'Attempt to attach widget with no parent element');
 
-    /**
-     * @return {boolean}
-     */
-    hasFocus: function()
-    {
-        return this.element.hasFocus();
-    },
+    if (!this._isRoot) {
+      // Update widget hierarchy.
+      var currentParent = parentElement;
+      while (currentParent && !currentParent.__widget)
+        currentParent = currentParent.parentElementOrShadowHost();
+      WebInspector.Widget.__assert(currentParent, 'Attempt to attach widget to orphan node');
+      this.attach(currentParent.__widget);
+    }
 
-    /**
-     * @return {!Size}
-     */
-    measurePreferredSize: function()
-    {
-        var document = this.element.ownerDocument;
-        var oldParent = this.element.parentElement;
-        var oldNextSibling = this.element.nextSibling;
-
-        WebInspector.Widget._originalAppendChild.call(document.body, this.element);
-        this.element.positionAt(0, 0);
-        var result = new Size(this.element.offsetWidth, this.element.offsetHeight);
-
-        this.element.positionAt(undefined, undefined);
-        if (oldParent)
-            WebInspector.Widget._originalInsertBefore.call(oldParent, this.element, oldNextSibling);
-        else
-            WebInspector.Widget._originalRemoveChild.call(document.body, this.element);
-        return result;
-    },
+    this.showWidget(parentElement, insertBefore);
+  }
+
+  /**
+   * @param {!WebInspector.Widget} parentWidget
+   */
+  attach(parentWidget) {
+    if (parentWidget === this._parentWidget)
+      return;
+    if (this._parentWidget)
+      this.detach();
+    this._parentWidget = parentWidget;
+    this._parentWidget._children.push(this);
+    this._isRoot = false;
+  }
+
+  /**
+   * @param {!Element} parentElement
+   * @param {?Element=} insertBefore
+   */
+  showWidget(parentElement, insertBefore) {
+    var currentParent = parentElement;
+    while (currentParent && !currentParent.__widget)
+      currentParent = currentParent.parentElementOrShadowHost();
+
+    if (this._isRoot)
+      WebInspector.Widget.__assert(!currentParent, 'Attempt to show root widget under another widget');
+    else
+      WebInspector.Widget.__assert(
+          currentParent && currentParent.__widget === this._parentWidget,
+          'Attempt to show under node belonging to alien widget');
+
+    var wasVisible = this._visible;
+    if (wasVisible && this.element.parentElement === parentElement)
+      return;
+
+    this._visible = true;
+
+    if (!wasVisible && this._parentIsShowing())
+      this._processWillShow();
+
+    this.element.classList.remove('hidden');
+
+    // Reparent
+    if (this.element.parentElement !== parentElement) {
+      WebInspector.Widget._incrementWidgetCounter(parentElement, this.element);
+      if (insertBefore)
+        WebInspector.Widget._originalInsertBefore.call(parentElement, this.element, insertBefore);
+      else
+        WebInspector.Widget._originalAppendChild.call(parentElement, this.element);
+    }
 
-    /**
-     * @return {!Constraints}
-     */
-    calculateConstraints: function()
-    {
-        return new Constraints();
-    },
+    if (!wasVisible && this._parentIsShowing())
+      this._processWasShown();
+
+    if (this._parentWidget && this._hasNonZeroConstraints())
+      this._parentWidget.invalidateConstraints();
+    else
+      this._processOnResize();
+  }
+
+  hideWidget() {
+    if (!this._parentWidget)
+      return;
+    this._hideWidget();
+  }
+
+  /**
+   * @param {boolean=} overrideHideOnDetach
+   */
+  _hideWidget(overrideHideOnDetach) {
+    if (!this._visible)
+      return;
+    this._visible = false;
+    var parentElement = this.element.parentElement;
 
-    /**
-     * @return {!Constraints}
-     */
-    constraints: function()
-    {
-        if (typeof this._constraints !== "undefined")
-            return this._constraints;
-        if (typeof this._cachedConstraints === "undefined")
-            this._cachedConstraints = this.calculateConstraints();
-        return this._cachedConstraints;
-    },
+    if (this._parentIsShowing())
+      this._processWillHide();
 
-    /**
-     * @param {number} width
-     * @param {number} height
-     * @param {number} preferredWidth
-     * @param {number} preferredHeight
-     */
-    setMinimumAndPreferredSizes: function(width, height, preferredWidth, preferredHeight)
-    {
-        this._constraints = new Constraints(new Size(width, height), new Size(preferredWidth, preferredHeight));
-        this.invalidateConstraints();
-    },
+    if (!overrideHideOnDetach && this.shouldHideOnDetach()) {
+      this.element.classList.add('hidden');
+    } else {
+      // Force legal removal
+      WebInspector.Widget._decrementWidgetCounter(parentElement, this.element);
+      WebInspector.Widget._originalRemoveChild.call(parentElement, this.element);
+    }
 
-    /**
-     * @param {number} width
-     * @param {number} height
-     */
-    setMinimumSize: function(width, height)
-    {
-        this._constraints = new Constraints(new Size(width, height));
-        this.invalidateConstraints();
-    },
+    if (this._parentIsShowing())
+      this._processWasHidden();
+    if (this._parentWidget && this._hasNonZeroConstraints())
+      this._parentWidget.invalidateConstraints();
+  }
+
+  detach() {
+    if (!this._parentWidget && !this._isRoot)
+      return;
+
+    if (this._visible)
+      this._hideWidget(true);
+
+    // Update widget hierarchy.
+    if (this._parentWidget) {
+      var childIndex = this._parentWidget._children.indexOf(this);
+      WebInspector.Widget.__assert(childIndex >= 0, 'Attempt to remove non-child widget');
+      this._parentWidget._children.splice(childIndex, 1);
+      if (this._parentWidget._defaultFocusedChild === this)
+        this._parentWidget._defaultFocusedChild = null;
+      this._parentWidget.childWasDetached(this);
+      var parent = this._parentWidget;
+      this._parentWidget = null;
+      this._processWasDetachedFromHierarchy();
+    } else {
+      WebInspector.Widget.__assert(this._isRoot, 'Removing non-root widget from DOM');
+    }
+  }
+
+  detachChildWidgets() {
+    var children = this._children.slice();
+    for (var i = 0; i < children.length; ++i)
+      children[i].detach();
+  }
+
+  /**
+   * @return {!Array.<!Element>}
+   */
+  elementsToRestoreScrollPositionsFor() {
+    return [this.element];
+  }
+
+  storeScrollPositions() {
+    var elements = this.elementsToRestoreScrollPositionsFor();
+    for (var i = 0; i < elements.length; ++i) {
+      var container = elements[i];
+      container._scrollTop = container.scrollTop;
+      container._scrollLeft = container.scrollLeft;
+    }
+  }
+
+  restoreScrollPositions() {
+    var elements = this.elementsToRestoreScrollPositionsFor();
+    for (var i = 0; i < elements.length; ++i) {
+      var container = elements[i];
+      if (container._scrollTop)
+        container.scrollTop = container._scrollTop;
+      if (container._scrollLeft)
+        container.scrollLeft = container._scrollLeft;
+    }
+  }
+
+  doResize() {
+    if (!this.isShowing())
+      return;
+    // No matter what notification we are in, dispatching onResize is not needed.
+    if (!this._inNotification())
+      this._callOnVisibleChildren(this._processOnResize);
+  }
+
+  doLayout() {
+    if (!this.isShowing())
+      return;
+    this._notify(this.onLayout);
+    this.doResize();
+  }
+
+  /**
+   * @param {string} cssFile
+   */
+  registerRequiredCSS(cssFile) {
+    WebInspector.appendStyle(this._isWebComponent ? this._shadowRoot : this.element, cssFile);
+  }
+
+  printWidgetHierarchy() {
+    var lines = [];
+    this._collectWidgetHierarchy('', lines);
+    console.log(lines.join('\n'));
+  }
+
+  _collectWidgetHierarchy(prefix, lines) {
+    lines.push(prefix + '[' + this.element.className + ']' + (this._children.length ? ' {' : ''));
+
+    for (var i = 0; i < this._children.length; ++i)
+      this._children[i]._collectWidgetHierarchy(prefix + '    ', lines);
+
+    if (this._children.length)
+      lines.push(prefix + '}');
+  }
+
+  /**
+   * @param {?Element} element
+   */
+  setDefaultFocusedElement(element) {
+    this._defaultFocusedElement = element;
+  }
+
+  /**
+   * @param {!WebInspector.Widget} child
+   */
+  setDefaultFocusedChild(child) {
+    WebInspector.Widget.__assert(child._parentWidget === this, 'Attempt to set non-child widget as default focused.');
+    this._defaultFocusedChild = child;
+  }
+
+  focus() {
+    if (!this.isShowing())
+      return;
+
+    var element = this._defaultFocusedElement;
+    if (element) {
+      if (!element.hasFocus())
+        element.focus();
+      return;
+    }
 
-    /**
-     * @return {boolean}
-     */
-    _hasNonZeroConstraints: function()
-    {
-        var constraints = this.constraints();
-        return !!(constraints.minimum.width || constraints.minimum.height || constraints.preferred.width || constraints.preferred.height);
-    },
-
-    suspendInvalidations()
-    {
-        ++this._invalidationsSuspended;
-    },
-
-    resumeInvalidations()
-    {
-        --this._invalidationsSuspended;
-        if (!this._invalidationsSuspended && this._invalidationsRequested)
-            this.invalidateConstraints();
-    },
-
-    invalidateConstraints: function()
-    {
-        if (this._invalidationsSuspended) {
-            this._invalidationsRequested = true;
-            return;
+    if (this._defaultFocusedChild && this._defaultFocusedChild._visible) {
+      this._defaultFocusedChild.focus();
+    } else {
+      for (var child of this._children) {
+        if (child._visible) {
+          child.focus();
+          break;
         }
-        this._invalidationsRequested = false;
-        var cached = this._cachedConstraints;
-        delete this._cachedConstraints;
-        var actual = this.constraints();
-        if (!actual.isEqual(cached) && this._parentWidget)
-            this._parentWidget.invalidateConstraints();
-        else
-            this.doLayout();
-    },
-
-    invalidateSize: function()
-    {
-        if (this._parentWidget)
-            this._parentWidget.doLayout();
-    },
-
-    __proto__: WebInspector.Object.prototype
+      }
+    }
+  }
+
+  /**
+   * @return {boolean}
+   */
+  hasFocus() {
+    return this.element.hasFocus();
+  }
+
+  /**
+   * @return {!Size}
+   */
+  measurePreferredSize() {
+    var document = this.element.ownerDocument;
+    var oldParent = this.element.parentElement;
+    var oldNextSibling = this.element.nextSibling;
+
+    WebInspector.Widget._originalAppendChild.call(document.body, this.element);
+    this.element.positionAt(0, 0);
+    var result = new Size(this.element.offsetWidth, this.element.offsetHeight);
+
+    this.element.positionAt(undefined, undefined);
+    if (oldParent)
+      WebInspector.Widget._originalInsertBefore.call(oldParent, this.element, oldNextSibling);
+    else
+      WebInspector.Widget._originalRemoveChild.call(document.body, this.element);
+    return result;
+  }
+
+  /**
+   * @return {!Constraints}
+   */
+  calculateConstraints() {
+    return new Constraints();
+  }
+
+  /**
+   * @return {!Constraints}
+   */
+  constraints() {
+    if (typeof this._constraints !== 'undefined')
+      return this._constraints;
+    if (typeof this._cachedConstraints === 'undefined')
+      this._cachedConstraints = this.calculateConstraints();
+    return this._cachedConstraints;
+  }
+
+  /**
+   * @param {number} width
+   * @param {number} height
+   * @param {number} preferredWidth
+   * @param {number} preferredHeight
+   */
+  setMinimumAndPreferredSizes(width, height, preferredWidth, preferredHeight) {
+    this._constraints = new Constraints(new Size(width, height), new Size(preferredWidth, preferredHeight));
+    this.invalidateConstraints();
+  }
+
+  /**
+   * @param {number} width
+   * @param {number} height
+   */
+  setMinimumSize(width, height) {
+    this._constraints = new Constraints(new Size(width, height));
+    this.invalidateConstraints();
+  }
+
+  /**
+   * @return {boolean}
+   */
+  _hasNonZeroConstraints() {
+    var constraints = this.constraints();
+    return !!(
+        constraints.minimum.width || constraints.minimum.height || constraints.preferred.width ||
+        constraints.preferred.height);
+  }
+
+  suspendInvalidations() {
+    ++this._invalidationsSuspended;
+  }
+
+  resumeInvalidations() {
+    --this._invalidationsSuspended;
+    if (!this._invalidationsSuspended && this._invalidationsRequested)
+      this.invalidateConstraints();
+  }
+
+  invalidateConstraints() {
+    if (this._invalidationsSuspended) {
+      this._invalidationsRequested = true;
+      return;
+    }
+    this._invalidationsRequested = false;
+    var cached = this._cachedConstraints;
+    delete this._cachedConstraints;
+    var actual = this.constraints();
+    if (!actual.isEqual(cached) && this._parentWidget)
+      this._parentWidget.invalidateConstraints();
+    else
+      this.doLayout();
+  }
+
+  invalidateSize() {
+    if (this._parentWidget)
+      this._parentWidget.doLayout();
+  }
 };
 
 WebInspector.Widget._originalAppendChild = Element.prototype.appendChild;
@@ -600,175 +598,116 @@ WebInspector.Widget._originalInsertBefore = Element.prototype.insertBefore;
 WebInspector.Widget._originalRemoveChild = Element.prototype.removeChild;
 WebInspector.Widget._originalRemoveChildren = Element.prototype.removeChildren;
 
-WebInspector.Widget._incrementWidgetCounter = function(parentElement, childElement)
-{
-    var count = (childElement.__widgetCounter || 0) + (childElement.__widget ? 1 : 0);
-    if (!count)
-        return;
-
-    while (parentElement) {
-        parentElement.__widgetCounter = (parentElement.__widgetCounter || 0) + count;
-        parentElement = parentElement.parentElementOrShadowHost();
-    }
-};
-
-WebInspector.Widget._decrementWidgetCounter = function(parentElement, childElement)
-{
-    var count = (childElement.__widgetCounter || 0) + (childElement.__widget ? 1 : 0);
-    if (!count)
-        return;
-
-    while (parentElement) {
-        parentElement.__widgetCounter -= count;
-        parentElement = parentElement.parentElementOrShadowHost();
-    }
-};
-
-WebInspector.Widget.__assert = function(condition, message)
-{
-    if (!condition) {
-        console.trace();
-        throw new Error(message);
-    }
-};
 
 /**
- * @param {?Node} node
+ * @unrestricted
  */
-WebInspector.Widget.focusWidgetForNode = function(node)
-{
-    while (node) {
-        if (node.__widget)
-            break;
-        node = node.parentNodeOrShadowHost();
-    }
-    if (!node)
-        return;
+WebInspector.VBox = class extends WebInspector.Widget {
+  /**
+   * @param {boolean=} isWebComponent
+   */
+  constructor(isWebComponent) {
+    super(isWebComponent);
+    this.contentElement.classList.add('vbox');
+  }
+
+  /**
+   * @override
+   * @return {!Constraints}
+   */
+  calculateConstraints() {
+    var constraints = new Constraints();
 
-    var widget = node.__widget;
-    while (widget._parentWidget) {
-        widget._parentWidget._defaultFocusedChild = widget;
-        widget = widget._parentWidget;
-    }
-};
-
-/**
- * @constructor
- * @extends {WebInspector.Widget}
- * @param {boolean=} isWebComponent
- */
-WebInspector.VBox = function(isWebComponent)
-{
-    WebInspector.Widget.call(this, isWebComponent);
-    this.contentElement.classList.add("vbox");
-};
-
-WebInspector.VBox.prototype = {
     /**
-     * @override
-     * @return {!Constraints}
+     * @this {!WebInspector.Widget}
+     * @suppressReceiverCheck
      */
-    calculateConstraints: function()
-    {
-        var constraints = new Constraints();
-
-        /**
-         * @this {!WebInspector.Widget}
-         * @suppressReceiverCheck
-         */
-        function updateForChild()
-        {
-            var child = this.constraints();
-            constraints = constraints.widthToMax(child);
-            constraints = constraints.addHeight(child);
-        }
-
-        this._callOnVisibleChildren(updateForChild);
-        return constraints;
-    },
+    function updateForChild() {
+      var child = this.constraints();
+      constraints = constraints.widthToMax(child);
+      constraints = constraints.addHeight(child);
+    }
 
-    __proto__: WebInspector.Widget.prototype
+    this._callOnVisibleChildren(updateForChild);
+    return constraints;
+  }
 };
 
 /**
- * @constructor
- * @extends {WebInspector.Widget}
- * @param {boolean=} isWebComponent
+ * @unrestricted
  */
-WebInspector.HBox = function(isWebComponent)
-{
-    WebInspector.Widget.call(this, isWebComponent);
-    this.contentElement.classList.add("hbox");
-};
+WebInspector.HBox = class extends WebInspector.Widget {
+  /**
+   * @param {boolean=} isWebComponent
+   */
+  constructor(isWebComponent) {
+    super(isWebComponent);
+    this.contentElement.classList.add('hbox');
+  }
+
+  /**
+   * @override
+   * @return {!Constraints}
+   */
+  calculateConstraints() {
+    var constraints = new Constraints();
 
-WebInspector.HBox.prototype = {
     /**
-     * @override
-     * @return {!Constraints}
+     * @this {!WebInspector.Widget}
+     * @suppressReceiverCheck
      */
-    calculateConstraints: function()
-    {
-        var constraints = new Constraints();
-
-        /**
-         * @this {!WebInspector.Widget}
-         * @suppressReceiverCheck
-         */
-        function updateForChild()
-        {
-            var child = this.constraints();
-            constraints = constraints.addWidth(child);
-            constraints = constraints.heightToMax(child);
-        }
-
-        this._callOnVisibleChildren(updateForChild);
-        return constraints;
-    },
+    function updateForChild() {
+      var child = this.constraints();
+      constraints = constraints.addWidth(child);
+      constraints = constraints.heightToMax(child);
+    }
 
-    __proto__: WebInspector.Widget.prototype
+    this._callOnVisibleChildren(updateForChild);
+    return constraints;
+  }
 };
 
 /**
- * @constructor
- * @extends {WebInspector.VBox}
- * @param {function()} resizeCallback
+ * @unrestricted
  */
-WebInspector.VBoxWithResizeCallback = function(resizeCallback)
-{
-    WebInspector.VBox.call(this);
+WebInspector.VBoxWithResizeCallback = class extends WebInspector.VBox {
+  /**
+   * @param {function()} resizeCallback
+   */
+  constructor(resizeCallback) {
+    super();
     this._resizeCallback = resizeCallback;
-};
-
-WebInspector.VBoxWithResizeCallback.prototype = {
-    onResize: function()
-    {
-        this._resizeCallback();
-    },
-
-    __proto__: WebInspector.VBox.prototype
+  }
+
+  /**
+   * @override
+   */
+  onResize() {
+    this._resizeCallback();
+  }
 };
 
 /**
- * @param {!WebInspector.Widget} widget
- * @constructor
+ * @unrestricted
  */
-WebInspector.WidgetFocusRestorer = function(widget)
-{
+WebInspector.WidgetFocusRestorer = class {
+  /**
+   * @param {!WebInspector.Widget} widget
+   */
+  constructor(widget) {
     this._widget = widget;
     this._previous = widget.element.ownerDocument.deepActiveElement();
     widget.focus();
-};
-
-WebInspector.WidgetFocusRestorer.prototype = {
-    restore: function()
-    {
-        if (!this._widget)
-            return;
-        if (this._widget.hasFocus() && this._previous)
-            this._previous.focus();
-        this._previous = null;
-        this._widget = null;
-    }
+  }
+
+  restore() {
+    if (!this._widget)
+      return;
+    if (this._widget.hasFocus() && this._previous)
+      this._previous.focus();
+    this._previous = null;
+    this._widget = null;
+  }
 };
 
 /**
@@ -777,10 +716,10 @@ WebInspector.WidgetFocusRestorer.prototype = {
  * @return {?Node}
  * @suppress {duplicate}
  */
-Element.prototype.appendChild = function(child)
-{
-    WebInspector.Widget.__assert(!child.__widget || child.parentElement === this, "Attempt to add widget via regular DOM operation.");
-    return WebInspector.Widget._originalAppendChild.call(this, child);
+Element.prototype.appendChild = function(child) {
+  WebInspector.Widget.__assert(
+      !child.__widget || child.parentElement === this, 'Attempt to add widget via regular DOM operation.');
+  return WebInspector.Widget._originalAppendChild.call(this, child);
 };
 
 /**
@@ -790,10 +729,10 @@ Element.prototype.appendChild = function(child)
  * @return {!Node}
  * @suppress {duplicate}
  */
-Element.prototype.insertBefore = function(child, anchor)
-{
-    WebInspector.Widget.__assert(!child.__widget || child.parentElement === this, "Attempt to add widget via regular DOM operation.");
-    return WebInspector.Widget._originalInsertBefore.call(this, child, anchor);
+Element.prototype.insertBefore = function(child, anchor) {
+  WebInspector.Widget.__assert(
+      !child.__widget || child.parentElement === this, 'Attempt to add widget via regular DOM operation.');
+  return WebInspector.Widget._originalInsertBefore.call(this, child, anchor);
 };
 
 /**
@@ -802,14 +741,15 @@ Element.prototype.insertBefore = function(child, anchor)
  * @return {!Node}
  * @suppress {duplicate}
  */
-Element.prototype.removeChild = function(child)
-{
-    WebInspector.Widget.__assert(!child.__widgetCounter && !child.__widget, "Attempt to remove element containing widget via regular DOM operation");
-    return WebInspector.Widget._originalRemoveChild.call(this, child);
+Element.prototype.removeChild = function(child) {
+  WebInspector.Widget.__assert(
+      !child.__widgetCounter && !child.__widget,
+      'Attempt to remove element containing widget via regular DOM operation');
+  return WebInspector.Widget._originalRemoveChild.call(this, child);
 };
 
-Element.prototype.removeChildren = function()
-{
-    WebInspector.Widget.__assert(!this.__widgetCounter, "Attempt to remove element containing widget via regular DOM operation");
-    WebInspector.Widget._originalRemoveChildren.call(this);
+Element.prototype.removeChildren = function() {
+  WebInspector.Widget.__assert(
+      !this.__widgetCounter, 'Attempt to remove element containing widget via regular DOM operation');
+  WebInspector.Widget._originalRemoveChildren.call(this);
 };