blink: Cleanup core class forward declarations

third_party/WebKit/Source/core/frame/FrameHost.h

 /*
  * Copyright (C) 2013 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 34 matching lines @@
 class ConsoleMessageStorage;
 class Deprecation;
 class EventHandlerRegistry;
 class OverscrollController;
 class Page;
 struct PageScaleConstraints;
 class PageScaleConstraintsSet;
 class Settings;
 class TopDocumentRootScrollerController;
 class UseCounter;
-class Visitor;
 class VisualViewport;
 
 // FrameHost is the set of global data shared between multiple frames
 // and is provided by the embedder to each frame when created.
 // FrameHost currently corresponds to the Page object in core/page
 // however the concept of a Page is moving up out of Blink.
 // In an out-of-process iframe world, a single Page may have
 // multiple frames in different process, thus Page becomes a
 // browser-level concept and Blink core/ only knows about its LocalFrame (and
 // FrameHost).  Separating Page from the rest of core/ through this indirection
@@ skipping 85 matching lines @@
   const Member<TopDocumentRootScrollerController>
       m_globalRootScrollerController;
 
   AtomicString m_overrideEncoding;
   int m_subframeCount;
 };
 
 }  // namespace blink
 
 #endif  // FrameHost_h