Pref service: expose all read-only PrefStores through Mojo

chrome/browser/BUILD.gn

Index: chrome/browser/BUILD.gn
diff --git a/chrome/browser/BUILD.gn b/chrome/browser/BUILD.gn
index 757c5429d8bc5e6b39ffdc10e83190e39b8b6bc9..f199f151083546f064d4b3bfba9c997fa758b8bf 100644
--- a/chrome/browser/BUILD.gn
+++ b/chrome/browser/BUILD.gn
@@ -1563,6 +1563,7 @@ split_static_library("browser") {
     "//printing/features",
     "//rlz/features",
     "//services/image_decoder/public/cpp",
+    "//services/preferences/public/cpp/",
     "//services/preferences/public/interfaces/",
     "//services/service_manager/public/cpp",
     "//services/shape_detection/public/interfaces",
@@ -4551,3 +4552,8 @@ service_manifest("preferences_manifest") {
   name = "preferences"
   source = "prefs/preferences_manifest.json"
 }
+
+service_manifest("preferences2_manifest") {
+  name = "preferences2"
+  source = "prefs/preferences2_manifest.json"
+}