cc: Add image to rect map in DiscardableImageMap.

cc/playback/display_item_list.cc

Index: cc/playback/display_item_list.cc
diff --git a/cc/playback/display_item_list.cc b/cc/playback/display_item_list.cc
index 69ed70dff9f394c4891f241aabf500d75c039697..722d62306f307633817bd3dc93e502383935a105 100644
--- a/cc/playback/display_item_list.cc
+++ b/cc/playback/display_item_list.cc
@@ -262,4 +262,8 @@ void DisplayItemList::GetDiscardableImagesInRect(
   image_map_.GetDiscardableImagesInRect(rect, contents_scale, images);
 }
 
+gfx::Rect DisplayItemList::GetRectForImage(ImageId image_id) const {
+  return image_map_.GetRectForImage(image_id);
+}
+
 }  // namespace cc