Have Document::fonts() return a raw pointer

Source/core/dom/Document.h

Index: Source/core/dom/Document.h
diff --git a/Source/core/dom/Document.h b/Source/core/dom/Document.h
index 54666feeba0bba260b46180fd8ec55a9ca150670..92f9db5df2a8204de99986af16892c8dc8c678e7 100644
--- a/Source/core/dom/Document.h
+++ b/Source/core/dom/Document.h
@@ -1059,7 +1059,8 @@ public:
     virtual DOMWindow* executingWindow() OVERRIDE { return domWindow(); }
     virtual void userEventWasHandled() OVERRIDE { resetLastHandledUserGestureTimestamp(); }
 
-    PassRefPtr<FontFaceSet> fonts();
+    // Can never return null.
+    FontFaceSet* fonts();
     DocumentLifecycleNotifier* lifecycleNotifier();
     bool isActive() const { return m_lifecyle.state() == DocumentLifecycle::Active; }
     bool isStopping() const { return m_lifecyle.state() == DocumentLifecycle::Stopping; }