Allow rewriting of Flash embeds in PluginDocument.

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

Index: third_party/WebKit/Source/core/html/PluginDocument.cpp
diff --git a/third_party/WebKit/Source/core/html/PluginDocument.cpp b/third_party/WebKit/Source/core/html/PluginDocument.cpp
index 8f4f31157243e27f541b4a4fd12e3c9aea1403af..62ee3fbecc3b5c955d445254b30ff77a1d83702f 100644
--- a/third_party/WebKit/Source/core/html/PluginDocument.cpp
+++ b/third_party/WebKit/Source/core/html/PluginDocument.cpp
@@ -179,7 +179,10 @@ Widget* PluginDocument::pluginWidget()
 {
     if (m_pluginNode && m_pluginNode->layoutObject()) {
         CHECK(m_pluginNode->layoutObject()->isEmbeddedObject());
-        return toLayoutEmbeddedObject(m_pluginNode->layoutObject())->widget();
+        Widget* widget = toLayoutEmbeddedObject(m_pluginNode->layoutObject())->widget();
+        if (!widget || !widget->isPluginContainer())
+            return nullptr;
+        return widget;
     }
     return 0;
 }