cc: Keep PaintImage in DrawImage.

cc/paint/discardable_image_store.h

Index: cc/paint/discardable_image_store.h
diff --git a/cc/paint/discardable_image_store.h b/cc/paint/discardable_image_store.h
index 426785c529a5acccf814c36d123a2d0212f9b049..ea1e828fc5e75df35e109339c7c2a4680d90c604 100644
--- a/cc/paint/discardable_image_store.h
+++ b/cc/paint/discardable_image_store.h
@@ -20,10 +20,11 @@ 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);
@@ -33,7 +34,7 @@ class CC_PAINT_EXPORT DiscardableImageStore {
   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,
@@ -43,14 +44,7 @@ class CC_PAINT_EXPORT DiscardableImageStore {
   // 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