Add chrome/service to GN build.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 30bce5a7feb417337fb0a23be8a58f17ba004fb7..f6939d794fa6f606f4c341906ec941df70a2f95d 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -27,6 +27,7 @@ group("root") {
     "//chrome/common",
     "//chrome/plugin",
     "//chrome/renderer",
+    "//chrome/service",
     "//chrome/utility",
     "//components:all_components",
     "//content",
@@ -146,6 +147,7 @@ group("root") {
       "//chrome/common",  # Blocked on content.
       "//chrome/plugin",  # Blocked on content.
       "//chrome/renderer",  # Blocked on content.
+      "//chrome/service",  # Blocked on content.
       "//chrome/utility",  # Blocked on content.
       "//content",
       "//extensions/common/api:extensions_api",