blink: Cleanup core class forward declarations

third_party/WebKit/Source/core/page/scrolling/ViewportScrollCallback.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ViewportScrollCallback_h
 #define ViewportScrollCallback_h
 
 #include "core/page/scrolling/ScrollStateCallback.h"
 #include "platform/heap/Handle.h"
 #include "platform/scroll/ScrollTypes.h"
 
 namespace blink {
 
 class BrowserControls;
-class FloatSize;
 class ScrollableArea;
 class ScrollState;
 class OverscrollController;
 class RootFrameViewport;
 
 // ViewportScrollCallback is a ScrollStateCallback, meaning that it's applied
 // during the applyScroll step of ScrollCustomization. It implements viewport
 // actions like moving browser controls and showing overscroll glow as well as
 // scrolling the Element.
 //
@@ skipping 37 matching lines @@
   ScrollResult performNativeScroll(ScrollState&);
 
   WeakMember<BrowserControls> m_browserControls;
   WeakMember<OverscrollController> m_overscrollController;
   WeakMember<RootFrameViewport> m_rootFrameViewport;
 };
 
 }  // namespace blink
 
 #endif  // ViewportScrollCallback_h