Remove the concept of user stylesheets.

Source/core/testing/Internals.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 217 matching lines @@
 
     String scrollingStateTreeAsText(Document*, ExceptionState&) const;
     String mainThreadScrollingReasons(Document*, ExceptionState&) const;
     PassRefPtr<ClientRectList> nonFastScrollableRects(Document*, ExceptionState&) const;
 
     void garbageCollectDocumentResources(Document*, ExceptionState&) const;
     void evictAllResources() const;
 
     void allowRoundingHacks() const;
 
-    void insertAuthorCSS(Document*, const String&) const;
-    void insertUserCSS(Document*, const String&) const;
-
     unsigned numberOfLiveNodes() const;
     unsigned numberOfLiveDocuments() const;
     Vector<String> consoleMessageArgumentCounts(Document*) const;
     PassRefPtr<DOMWindow> openDummyInspectorFrontend(const String& url);
     void closeDummyInspectorFrontend();
     Vector<unsigned long> setMemoryCacheCapacities(unsigned long minDeadBytes, unsigned long maxDeadBytes, unsigned long totalBytes);
     void setInspectorResourcesDataSizeLimits(int maximumResourcesContentSize, int maximumSingleResourceContentSize, ExceptionState&);
 
     String counterValue(Element*);
 
@@ skipping 59 matching lines @@
     RefPtr<DOMWindow> m_frontendWindow;
     OwnPtr<InspectorFrontendChannelDummy> m_frontendChannel;
     RefPtr<InternalRuntimeFlags> m_runtimeFlags;
     RefPtr<ScrollingCoordinator> m_scrollingCoordinator;
     RefPtr<InternalProfilers> m_profilers;
 };
 
 } // namespace WebCore
 
 #endif