Change skia build files to use a utils.gypi instead of hardcoded files.

skia/BUILD.gn

Index: skia/BUILD.gn
diff --git a/skia/BUILD.gn b/skia/BUILD.gn
index 74f6843d3ba30bf512abee72ba8ff9ab78e227be..ca888e55f7ae5d22679ab5fe3d779db2c25515ef 100644
--- a/skia/BUILD.gn
+++ b/skia/BUILD.gn
@@ -56,6 +56,15 @@ gypi_skia_effects = exec_script(
     "scope",
     [ "//third_party/skia/gyp/effects.gypi" ])
 
+# The list of Skia utilss that are to be set for chromium.
+gypi_skia_utils = exec_script(
+    "//build/gypi_to_gn.py",
+    [ rebase_path("//third_party/skia/gyp/utils.gypi"),
+      "--replace=<(skia_include_path)=//third_party/skia/include",
+      "--replace=<(skia_src_path)=//third_party/skia/src" ],
+    "scope",
+    [ "//third_party/skia/gyp/utils.gypi" ])
+
 # The list of Skia files is kept in skia_gn_files.gypi. Read it.
 gypi_values = exec_script(
     "//build/gypi_to_gn.py",
@@ -295,6 +304,7 @@ component("skia") {
   # The skia gypi values are relative to the skia_dir, so we need to rebase.
   sources += gypi_skia_core.sources
   sources += gypi_skia_effects.sources
+  sources += gypi_skia_utils.sources
   sources += gypi_skia_pdf.sources
   sources += gypi_values.skia_library_sources