Update from https://crrev.com/311076

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 "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;
 
  protected:
   DisplayItem();
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_DISPLAY_ITEM_H_