Remove parts of //cc we aren't using

cc/resources/display_item.h

-// Copyright 2014 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 CC_RESOURCES_DISPLAY_ITEM_H_
-#define CC_RESOURCES_DISPLAY_ITEM_H_
-
-#include "base/memory/scoped_ptr.h"
-#include "cc/base/cc_export.h"
-#include "cc/debug/traced_value.h"
-#include "ui/gfx/geometry/rect.h"
-
-class SkCanvas;
-class SkDrawPictureCallback;
-
-namespace cc {
-
-class CC_EXPORT DisplayItem {
- public:
-  virtual ~DisplayItem() {}
-
-  virtual void Raster(SkCanvas* canvas,
-                      SkDrawPictureCallback* callback) const = 0;
-  virtual void RasterForTracing(SkCanvas* canvas) const;
-
-  virtual bool IsSuitableForGpuRasterization() const = 0;
-  virtual int ApproximateOpCount() const = 0;
-  virtual size_t PictureMemoryUsage() const = 0;
-  virtual void AsValueInto(base::trace_event::TracedValue* array) const = 0;
-
- protected:
-  DisplayItem();
-};
-
-}  // namespace cc
-
-#endif  // CC_RESOURCES_DISPLAY_ITEM_H_