Add support for a managed user pref store to PrefService.

base/prefs/pref_value_store.h

Index: base/prefs/pref_value_store.h
diff --git a/base/prefs/pref_value_store.h b/base/prefs/pref_value_store.h
index 4036e40ac87b99d0b44e59456bae556e0824014f..4f43962ab9427a097c86553023e7ed317515ec0b 100644
--- a/base/prefs/pref_value_store.h
+++ b/base/prefs/pref_value_store.h
@@ -44,6 +44,7 @@ class BASE_PREFS_EXPORT PrefValueStore {
   // |pref_notifier| facilitates broadcasting preference change notifications
   // to the world.
   PrefValueStore(PrefStore* managed_prefs,
+                 PrefStore* managed_user_prefs,
                  PrefStore* extension_prefs,
                  PrefStore* command_line_prefs,
                  PrefStore* user_prefs,
@@ -55,6 +56,7 @@ class BASE_PREFS_EXPORT PrefValueStore {
   // Creates a clone of this PrefValueStore with PrefStores overwritten
   // by the parameters passed, if unequal NULL.
   PrefValueStore* CloneAndSpecialize(PrefStore* managed_prefs,
+                                     PrefStore* managed_user_prefs,
                                      PrefStore* extension_prefs,
                                      PrefStore* command_line_prefs,
                                      PrefStore* user_prefs,
@@ -116,6 +118,7 @@ class BASE_PREFS_EXPORT PrefValueStore {
   // PrefStores must be listed here in order from highest to lowest priority.
   //   MANAGED contains all managed preference values that are provided by
   //      mandatory policies (e.g. Windows Group Policy or cloud policy).
+  //   MANAGED_USER contains preferences that are valid for managed users.
   //   EXTENSION contains preference values set by extensions.
   //   COMMAND_LINE contains preference values set by command-line switches.
   //   USER contains all user-set preference values.
@@ -127,6 +130,7 @@ class BASE_PREFS_EXPORT PrefValueStore {
     // an invalid marker, e.g. as a return value.
     INVALID_STORE = -1,
     MANAGED_STORE = 0,
+    MANAGED_USER_STORE,
     EXTENSION_STORE,
     COMMAND_LINE_STORE,
     USER_STORE,