Make FrameDestructionObserver::m_frame a private.

Source/core/plugins/DOMMimeType.h

 /*
     Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.
 
     This library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 34 matching lines @@
     virtual ~DOMMimeType();
 
     const String& type() const;
     String suffixes() const;
     const String& description() const;
     PassRefPtrWillBeRawPtr<DOMPlugin> enabledPlugin() const;
 
     virtual void trace(Visitor*) override;
 
 private:
+    DOMMimeType(PassRefPtr<PluginData>, LocalFrame*, unsigned index);
+
     const MimeClassInfo& mimeClassInfo() const { return m_pluginData->mimes()[m_index]; }
 
-    DOMMimeType(PassRefPtr<PluginData>, LocalFrame*, unsigned index);
     RefPtr<PluginData> m_pluginData;
     unsigned m_index;
 };
 
 } // namespace blink
 
 #endif // DOMMimeType_h