Move the Widget hierarchy to the Oilpan heap.

Source/core/loader/EmptyClients.cpp

Index: Source/core/loader/EmptyClients.cpp
diff --git a/Source/core/loader/EmptyClients.cpp b/Source/core/loader/EmptyClients.cpp
index 3dd6b1e30b9cb1d2c67068bcc2278669d33b6207..beaa27a516a01301c7ab6f29b4bd77ce481ecfa4 100644
--- a/Source/core/loader/EmptyClients.cpp
+++ b/Source/core/loader/EmptyClients.cpp
@@ -127,12 +127,12 @@ PassRefPtrWillBeRawPtr<LocalFrame> EmptyFrameLoaderClient::createFrame(const KUR
     return nullptr;
 }
 
-PassRefPtr<Widget> EmptyFrameLoaderClient::createPlugin(HTMLPlugInElement*, const KURL&, const Vector<String>&, const Vector<String>&, const String&, bool, DetachedPluginPolicy)
+PassRefPtrWillBeRawPtr<Widget> EmptyFrameLoaderClient::createPlugin(HTMLPlugInElement*, const KURL&, const Vector<String>&, const Vector<String>&, const String&, bool, DetachedPluginPolicy)
 {
     return nullptr;
 }
 
-PassRefPtr<Widget> EmptyFrameLoaderClient::createJavaAppletWidget(HTMLAppletElement*, const KURL&, const Vector<String>&, const Vector<String>&)
+PassRefPtrWillBeRawPtr<Widget> EmptyFrameLoaderClient::createJavaAppletWidget(HTMLAppletElement*, const KURL&, const Vector<String>&, const Vector<String>&)
 {
     return nullptr;
 }