cc: Record mip levels used for downscaling images in the renderer.

Bug: 729183
Change-Id: I4e5b3251048d57d592bb82e933d23adab146a31d
Reviewed-on: https://chromium-review.googlesource.com/568662
Commit-Queue: Khushal <khushalsagar@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Reviewed-by: Eric Karl <ericrk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#487221}

diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index 3a68d81..29f538f 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn

@@ -345,6 +345,7 @@
     "tiles/gpu_image_decode_cache.h",
     "tiles/image_controller.cc",
     "tiles/image_controller.h",
+    "tiles/image_decode_cache.cc",
     "tiles/image_decode_cache.h",
     "tiles/mipmap_util.cc",
     "tiles/mipmap_util.h",