cc: Keep PaintImage in DrawImage.

cc/tiles/image_controller.h

 // Copyright 2016 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_TILES_IMAGE_CONTROLLER_H_
 #define CC_TILES_IMAGE_CONTROLLER_H_
 
 #include <set>
 #include <vector>
 
@@ skipping 102 matching lines @@
   std::map<ImageDecodeRequestId, ImageDecodeRequest>
       requests_needing_completion_;
   bool abort_tasks_ = false;
   // Orphaned requests are requests that were either in queue or needed a
   // completion callback when we set the decode cache to be nullptr. When a new
   // decode cache is set, these requests are re-enqueued again with tasks
   // generated by the new cache. Note that when the cache is set, then aside
   // from generating new tasks, this vector should be empty.
   std::vector<ImageDecodeRequest> orphaned_decode_requests_;
 
+  // The id used for DrawImages created by the controller for requests made to
+  // the image decode service.
+  PaintImage::Id paint_image_id_;
+
   base::WeakPtrFactory<ImageController> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ImageController);
 };
 
 }  // namespace cc
 
 #endif  // CC_TILES_IMAGE_CONTROLLER_H_