Constify SkPicture in DrawingDisplayItem (cc side)

cc/resources/drawing_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_DRAWING_DISPLAY_ITEM_H_
 #define CC_RESOURCES_DRAWING_DISPLAY_ITEM_H_
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
 #include "cc/resources/display_item.h"
 #include "skia/ext/refptr.h"
-#include "ui/gfx/geometry/point_f.h"
 
 class SkCanvas;
 class SkDrawPictureCallback;
 class SkPicture;
 
 namespace cc {
 
 class CC_EXPORT DrawingDisplayItem : public DisplayItem {
  public:
   ~DrawingDisplayItem() override;
 
-  static scoped_ptr<DrawingDisplayItem> Create(skia::RefPtr<SkPicture> picture,
-                                               gfx::PointF location) {
-    return make_scoped_ptr(new DrawingDisplayItem(picture, location));
+  static scoped_ptr<DrawingDisplayItem> Create(
+      skia::RefPtr<const SkPicture> picture) {
+    return make_scoped_ptr(new DrawingDisplayItem(picture));
   }
 
   void Raster(SkCanvas* canvas, SkDrawPictureCallback* callback) const override;
   void RasterForTracing(SkCanvas* canvas) const override;
 
   bool IsSuitableForGpuRasterization() const override;
   int ApproximateOpCount() const override;
   size_t PictureMemoryUsage() const override;
   void AsValueInto(base::trace_event::TracedValue* array) const override;
 
  protected:
-  DrawingDisplayItem(skia::RefPtr<SkPicture> picture, gfx::PointF location);
+  explicit DrawingDisplayItem(skia::RefPtr<const SkPicture> picture);
 
  private:
-  skia::RefPtr<SkPicture> picture_;
-  gfx::PointF location_;
+  skia::RefPtr<const SkPicture> picture_;
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_DRAWING_DISPLAY_ITEM_H_