Pref service: support for incognito prefs

components/prefs/pref_value_store.h

Index: components/prefs/pref_value_store.h
diff --git a/components/prefs/pref_value_store.h b/components/prefs/pref_value_store.h
index eeab3062fbe293b039c6c2f69c8f6421c4b69385..79767d3ad09af50d1f0f4262e039b35fe6e2ae0e 100644
--- a/components/prefs/pref_value_store.h
+++ b/components/prefs/pref_value_store.h
@@ -38,6 +38,8 @@ class COMPONENTS_PREFS_EXPORT PrefValueStore {
   //   EXTENSION contains preference values set by extensions.
   //   COMMAND_LINE contains preference values set by command-line switches.
   //   USER contains all user-set preference values.
+  //   INCOGNITO_STORE contains preferences that were written while in incognito
+  //      mode.
   //   RECOMMENDED contains all preferences that are provided by recommended
   //      policies.
   //   DEFAULT contains all application default preference values.
@@ -50,6 +52,7 @@ class COMPONENTS_PREFS_EXPORT PrefValueStore {
     EXTENSION_STORE,
     COMMAND_LINE_STORE,
     USER_STORE,
+    INCOGNITO_STORE,
     RECOMMENDED_STORE,
     DEFAULT_STORE,
     PREF_STORE_TYPE_MAX = DEFAULT_STORE