Oilpan: always limit persisted plugin disposal to PluginViews instances.

third_party/WebKit/Source/core/html/HTMLPlugInElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLPlugInElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLPlugInElement.cpp b/third_party/WebKit/Source/core/html/HTMLPlugInElement.cpp
index 8f6b0c971926021cadefbd87bfb8ef19a226dbf8..882aed58d675ad61db1d5f7e5f740c59e287ae34 100644
--- a/third_party/WebKit/Source/core/html/HTMLPlugInElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLPlugInElement.cpp
@@ -94,7 +94,10 @@ DEFINE_TRACE(HTMLPlugInElement)
 void HTMLPlugInElement::disconnectContentFrame()
 {
     if (m_persistedPluginWidget) {
-        m_persistedPluginWidget->dispose();
+        if (m_persistedPluginWidget->isPluginView())
+            m_persistedPluginWidget->dispose();
+        else
+            ASSERT(m_persistedPluginWidget->isFrameView());
         m_persistedPluginWidget = nullptr;
     }
     HTMLFrameOwnerElement::disconnectContentFrame();
@@ -115,8 +118,12 @@ void HTMLPlugInElement::setPersistedPluginWidget(Widget* widget)
     unregisterAsRenderlessIfNeeded();
     registerAsRenderless(widget);
     if (m_persistedPluginWidget) {
-        m_persistedPluginWidget->hide();
-        m_persistedPluginWidget->dispose();
+        if (m_persistedPluginWidget->isPluginView()) {
+            m_persistedPluginWidget->hide();
+            m_persistedPluginWidget->dispose();
+        } else {
+            ASSERT(m_persistedPluginWidget->isFrameView());
+        }
     }
 #endif
     m_persistedPluginWidget = widget;