DevTools: follow up to the widget hierarchy change, account for local widget reparending.

Review-Url: https://codereview.chromium.org/2180853003
Cr-Commit-Position: refs/heads/master@{#407705}

third_party/WebKit/LayoutTests/inspector/components/widget-events-expected.txt

@@ -244,3 +244,15 @@ Parent()
 Child()
 Error: Attempt to show under node belonging to alien widget
 
+Running: testReparentWithinWidget
+Parent()
+Parent.show()
+  Parent.wasShown()
+  Parent.onResize()
+Child()
+Child.show()
+  Child.wasShown()
+  Child.onResize()
+Child.show()
+  Child.onResize()
+

third_party/WebKit/LayoutTests/inspector/components/widget-events.html

@@ -355,6 +355,18 @@ function test()
                 InspectorTest.addResult(e);
             }
             next();
+        },
+
+        function testReparentWithinWidget(next)
+        {
+            var parentWidget = new TestWidget("Parent");
+            parentWidget.show(WebInspector.inspectorView.element);
+            var childWidget = new TestWidget("Child");
+            var container1 = parentWidget.element.createChild("div");
+            var container2 = parentWidget.element.createChild("div");
+            childWidget.show(container1);
+            childWidget.show(container2);
+            next();
         }
     ]);
 }

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

@@ -256,11 +256,13 @@ WebInspector.Widget.prototype = {
         else
             WebInspector.Widget.__assert(currentParent && currentParent.__widget === this._parentWidget, "Attempt to show under node belonging to alien widget");
 
-        if (this._visible)
+        var wasVisible = this._visible;
+        if (wasVisible && this.element.parentElement === parentElement)
             return;
+
         this._visible = true;
 
-        if (this._parentIsShowing())
+        if (!wasVisible && this._parentIsShowing())
             this._processWillShow();
 
         this.element.classList.remove("hidden");
@@ -274,7 +276,7 @@ WebInspector.Widget.prototype = {
                 WebInspector.Widget._originalAppendChild.call(parentElement, this.element);
         }
 
-        if (this._parentIsShowing())
+        if (!wasVisible && this._parentIsShowing())
             this._processWasShown();
 
         if (this._parentWidget && this._hasNonZeroConstraints())