[DevTools] Rework some focus code.

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

Index: third_party/WebKit/Source/devtools/front_end/ui/Dialog.js
diff --git a/third_party/WebKit/Source/devtools/front_end/ui/Dialog.js b/third_party/WebKit/Source/devtools/front_end/ui/Dialog.js
index 7b8c44354ecaf8597dc80fb42d92d823c4ac98e9..5499b122a90d35a70555c884b0f3275661206458 100644
--- a/third_party/WebKit/Source/devtools/front_end/ui/Dialog.js
+++ b/third_party/WebKit/Source/devtools/front_end/ui/Dialog.js
@@ -74,14 +74,10 @@ WebInspector.Dialog.prototype = {
         this._glassPane.element.addEventListener("click", this._onGlassPaneClick.bind(this), false);
         this.element.ownerDocument.body.addEventListener("keydown", this._keyDownBound, false);
 
-        // When a dialog closes, focus should be restored to the previous focused element when
-        // possible, otherwise the default inspector view element.
-        WebInspector.Dialog._previousFocusedElement = WebInspector.currentFocusElement();
-
         WebInspector.Widget.prototype.show.call(this, this._glassPane.element);
 
         this._position();
-        this.focus();
+        this._focusRestorer = new WebInspector.WidgetFocusRestorer(this);
     },
 
     /**
@@ -89,16 +85,14 @@ WebInspector.Dialog.prototype = {
      */
     detach: function()
     {
+        this._focusRestorer.restore();
+
         this.element.ownerDocument.body.removeEventListener("keydown", this._keyDownBound, false);
         WebInspector.Widget.prototype.detach.call(this);
 
         this._glassPane.dispose();
         delete this._glassPane;
 
-        if (WebInspector.Dialog._previousFocusedElement)
-            WebInspector.Dialog._previousFocusedElement.focus();
-        delete WebInspector.Dialog._previousFocusedElement;
-
         this._restoreTabIndexOnElements();
 
         delete WebInspector.Dialog._instance;