Adds skia/config/SkUserConfig.h to skia_library.gypi

BUG=401542
TEST=none
R=senorblanco@chromium.org

Review URL: https://codereview.chromium.org/466223008

Cr-Commit-Position: refs/heads/master@{#291787}

skia/BUILD.gn

@@ -250,6 +250,7 @@ config("skia_library_config") {
 component("skia") {
   sources = [
     # Chrome sources.
+    "config/SkUserConfig.h",
     "ext/analysis_canvas.cc",
     "ext/analysis_canvas.h",
     "ext/benchmarking_canvas.cc",

skia/skia_chrome.gypi

@@ -27,6 +27,8 @@
     ],
   },
   'sources': [
+    'config/SkUserConfig.h',
+
     # Note: file list duplicated in GN build.
     'ext/analysis_canvas.cc',
     'ext/analysis_canvas.h',