DevTools: Remember the last focused widget.

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

 /*
  * Copyright (C) 2008 Apple Inc. All Rights Reserved.
  * Copyright (C) 2011 Google Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 30 matching lines @@
     }
     this._isWebComponent = isWebComponent;
     this.element.__widget = this;
     this._visible = false;
     this._isRoot = false;
     this._isShowing = false;
     this._children = [];
     this._hideOnDetach = false;
     this._notificationDepth = 0;
     this._invalidationsSuspended = 0;
+    this._lastFocusedChild = null;
 }
 
 WebInspector.Widget.prototype = {
     markAsRoot: function()
     {
         WebInspector.Widget.__assert(!this.element.parentElement, "Attempt to mark as root attached node");
         this._isRoot = true;
     },
 
     /**
@@ skipping 170 matching lines @@
      * @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);
+        if (!this._parentWidget._lastFocusedChild)
+            this._parentWidget._lastFocusedChild = this;
         this._isRoot = false;
     },
 
     /**
      * @param {!Element} parentElement
      * @param {?Element=} insertBefore
      */
     showWidget: function(parentElement, insertBefore)
     {
         var currentParent = parentElement;
@@ skipping 74 matching lines @@
             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._lastFocusedChild === this)
+                this._parentWidget._lastFocusedChild = this._parentWidget._children[0] || null;
             this._parentWidget.childWasDetached(this);
             var parent = this._parentWidget;
             this._parentWidget = null;
         } else {
             WebInspector.Widget.__assert(this._isRoot, "Removing non-root widget from DOM");
         }
     },
 
     detachChildWidgets: function()
     {
@@ skipping 76 matching lines @@
     },
 
     /**
      * @param {!Element} element
      */
     setDefaultFocusedElement: function(element)
     {
         this._defaultFocusedElement = element;
     },
 
+    makeDefaultFocused: function()

[pfeldman, 2016/09/08 00:53:50]

I'd rather have it on the parent.

+    {
+        if (this._parentWidget)
+            this._parentWidget._lastFocusedChild = this;

[pfeldman, 2016/09/08 00:53:50]

You should now call it defaultFocusChild...

+    },
+
     focus: function()
     {
         var element = this._defaultFocusedElement;
         if (element && !element.isAncestor(this.element.ownerDocument.activeElement)) {
             WebInspector.setCurrentFocusElement(element);
             return;
         }
 
-        if (this._children.length)
-            this._children[0].focus();
+        if (this._lastFocusedChild)
+            this._lastFocusedChild.focus();
+    },
+
+    _wasFocused: function()
+    {
+        var widget = this;
+        while (widget._parentWidget) {
+            widget._parentWidget._lastFocusedChild = widget;
+            widget = widget._parentWidget;
+        }
     },
 
     /**
      * @return {boolean}
      */
     hasFocus: function()
     {
         var activeElement = this.element.ownerDocument.activeElement;
         return activeElement && activeElement.isSelfOrDescendant(this.element);
     },
@@ skipping 138 matching lines @@
 
 WebInspector.Widget.__assert = function(condition, message)
 {
     if (!condition) {
         console.trace();
         throw new Error(message);
     }
 }
 
 /**
+ * @param {?Node} node
+ */
+WebInspector.Widget.focusWidgetForNode = function(node)
+{
+    while (node) {
+        if (node.__widget) {
+            node.__widget._wasFocused();
+            return;
+        }
+        node = node.parentNodeOrShadowHost();
+    }
+}
+
+/**
  * @constructor
  * @extends {WebInspector.Widget}
  * @param {boolean=} isWebComponent
  */
 WebInspector.VBox = function(isWebComponent)
 {
     WebInspector.Widget.call(this, isWebComponent);
     this.contentElement.classList.add("vbox");
 };
 
@@ skipping 117 matching lines @@
 {
     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);
 }