Add SkLRUCache.h to core.gni.

It wasn't listed in gn so didn't show up in editors as a known file in
projects.

Change-Id: Ie01773489dd72f055f04785ca7f21b6bdef6a3f7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/290541
Commit-Queue: Ben Wagner <bungeman@google.com>
Auto-Submit: Ben Wagner <bungeman@google.com>
Reviewed-by: Herb Derby <herb@google.com>
diff --git a/gn/core.gni b/gn/core.gni
index 6dac1b8..dbfa92d 100644
--- a/gn/core.gni
+++ b/gn/core.gni
@@ -234,6 +234,7 @@
   "$_src/core/SkImageFilter_Base.h",
   "$_src/core/SkImageGenerator.cpp",
   "$_src/core/SkImageInfo.cpp",
+  "$_src/core/SkLRUCache.h",
   "$_src/core/SkLatticeIter.cpp",
   "$_src/core/SkLatticeIter.h",
   "$_src/core/SkLegacyGpuBlurUtils.cpp",