cc: Keep PaintImage in DrawImage.

cc/tiles/image_controller.h

Index: cc/tiles/image_controller.h
diff --git a/cc/tiles/image_controller.h b/cc/tiles/image_controller.h
index 940a7fd842c7a3468ebd7c1f21276e003d9150dc..b2ab44a571bcbc1f14f15ec3f267d87f54df66df 100644
--- a/cc/tiles/image_controller.h
+++ b/cc/tiles/image_controller.h
@@ -120,6 +120,10 @@ class CC_EXPORT ImageController {
   // 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);