Move PrefStoreManagerImpl into //services/preferences.

services/preferences/public/cpp/BUILD.gn

Index: services/preferences/public/cpp/BUILD.gn
diff --git a/services/preferences/public/cpp/BUILD.gn b/services/preferences/public/cpp/BUILD.gn
index dd54f570ad8622dc250cd30832d1ec250a391343..a672c5325678c67b4bea412621920530688c2007 100644
--- a/services/preferences/public/cpp/BUILD.gn
+++ b/services/preferences/public/cpp/BUILD.gn
@@ -18,19 +18,29 @@ source_set("cpp") {
     "pref_store_client_mixin.h",
     "pref_store_impl.cc",
     "pref_store_impl.h",
-    "pref_store_manager_impl.cc",
-    "pref_store_manager_impl.h",
   ]
 
   public_deps = [
     "//base",
-    "//components/prefs:prefs",
+    "//components/prefs",
     "//services/preferences/public/interfaces",
     "//services/service_manager/public/cpp",
   ]
 
   deps = [
-    "//mojo/public/cpp/bindings:bindings",
+    "//mojo/public/cpp/bindings",
+  ]
+}
+
+source_set("service_main") {
+  deps = [
+    "//base",
+    "//components/prefs",
     "//services/preferences",
+    "//services/service_manager/public/cpp",
+  ]
+  sources = [
+    "pref_service_main.cc",
+    "pref_service_main.h",
   ]
 }