Persist plugins over reattach.

Source/core/html/HTMLPlugInElement.cpp

Index: Source/core/html/HTMLPlugInElement.cpp
diff --git a/Source/core/html/HTMLPlugInElement.cpp b/Source/core/html/HTMLPlugInElement.cpp
index cde57a859cdcdc7988fd99d701bf3571e05cf17c..a93b6f11ffc9845830ee5a861d64ea5c92c68500 100644
--- a/Source/core/html/HTMLPlugInElement.cpp
+++ b/Source/core/html/HTMLPlugInElement.cpp
@@ -163,8 +163,15 @@ void HTMLPlugInElement::attach(const AttachContext& context)
 {
     HTMLFrameOwnerElement::attach(context);
 
-    if (!layoutObject() || useFallbackContent())
+    if (!layoutObject() || useFallbackContent()) {
+        // If we don't have a layoutObject we have to dispose of any plugins
+        // which we persisted over a reattach.
+        if (m_persistedPluginWidget) {
+            HTMLFrameOwnerElement::UpdateSuspendScope suspendWidgetHierarchyUpdates;
+            setPersistedPluginWidget(nullptr);
+        }
         return;
+    }
 
     if (isImageType()) {
         if (!m_imageLoader)
@@ -191,6 +198,17 @@ void HTMLPlugInElement::updateWidget()
     }
 }
 
+void HTMLPlugInElement::removedFrom(ContainerNode* insertionPoint)
+{
+    // If we've persisted the plugin and we're removed from the tree then
+    // make sure we cleanup the persistance pointer.
+    if (m_persistedPluginWidget) {
+        HTMLFrameOwnerElement::UpdateSuspendScope suspendWidgetHierarchyUpdates;
+        setPersistedPluginWidget(nullptr);
+    }
+    HTMLFrameOwnerElement::removedFrom(insertionPoint);
+}
+
 void HTMLPlugInElement::requestPluginCreationWithoutLayoutObjectIfPossible()
 {
     if (m_serviceType.isEmpty())
@@ -241,7 +259,7 @@ void HTMLPlugInElement::detach(const AttachContext& context)
 
     // Only try to persist a plugin widget we actually own.
     Widget* plugin = ownedWidget();
-    if (plugin && plugin->pluginShouldPersist())
+    if (plugin && context.performingReattach)
         setPersistedPluginWidget(plugin);
 
     resetInstance();