cc: Keep PaintImage in DrawImage.

cc/paint/discardable_image_store.h

 // Copyright 2017 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_PAINT_DISCARDABLE_IMAGE_STORE_H_
 #define CC_PAINT_DISCARDABLE_IMAGE_STORE_H_
 
 #include "base/containers/flat_map.h"
 #include "cc/paint/draw_image.h"
 #include "cc/paint/image_id.h"
 #include "cc/paint/paint_export.h"
 #include "cc/paint/paint_op_buffer.h"
 #include "third_party/skia/include/core/SkMatrix.h"
 #include "third_party/skia/include/core/SkRect.h"
 #include "third_party/skia/include/utils/SkNoDrawCanvas.h"
 
 namespace cc {
 class PaintFlags;
 class PaintImage;
 
 class CC_PAINT_EXPORT DiscardableImageStore {
  public:
-  DiscardableImageStore(int width,
-                        int height,
-                        std::vector<std::pair<DrawImage, gfx::Rect>>* image_set,
-                        base::flat_map<ImageId, gfx::Rect>* image_id_to_rect);
+  DiscardableImageStore(
+      int width,
+      int height,
+      std::vector<std::pair<DrawImage, gfx::Rect>>* image_set,
+      base::flat_map<PaintImage::Id, gfx::Rect>* image_id_to_rect);
   ~DiscardableImageStore();
 
   void GatherDiscardableImages(const PaintOpBuffer* buffer);
   SkNoDrawCanvas* GetNoDrawCanvas();
 
  private:
   class PaintTrackingCanvas;
 
   void AddImageFromFlags(const SkRect& rect, const PaintFlags& flags);
-  void AddImage(const PaintImage& paint_image,
+  void AddImage(PaintImage paint_image,
                 const SkRect& src_rect,
                 const SkRect& rect,
                 const SkMatrix* local_matrix,
                 const PaintFlags& flags);
 
   // This canvas is used only for tracking transform/clip/filter state from the
   // non-drawing ops.
   std::unique_ptr<PaintTrackingCanvas> canvas_;
   std::vector<std::pair<DrawImage, gfx::Rect>>* image_set_;
-  base::flat_map<ImageId, gfx::Rect>* image_id_to_rect_;
-  // This is currently used for images that come from shaders. We don't know
-  // what the stable id is, but since the completion and animation states are
-  // both unknown, this value doesn't matter as it won't be used in checker
-  // imaging anyway. Keep this value the same to avoid id churn.
-  // TODO(vmpstr): Remove this when we can add paint images into shaders
-  // directly.
-  PaintImage::Id unknown_stable_id_;
+  base::flat_map<PaintImage::Id, gfx::Rect>* image_id_to_rect_;
 };
 
 }  // namespace cc
 
 #endif  // CC_PAINT_DISCARDABLE_IMAGE_STORE_H_