Converted IncognitoForced boolean policy into IncognitoModeAvailability enum policy.

chrome/browser/prefs/pref_value_map.cc

Index: chrome/browser/prefs/pref_value_map.cc
diff --git a/chrome/browser/prefs/pref_value_map.cc b/chrome/browser/prefs/pref_value_map.cc
index b810519bbb27795d59960c27c283ebdb571553d7..3d69cf160dee72610500222f04c591b6d7ee8808 100644
--- a/chrome/browser/prefs/pref_value_map.cc
+++ b/chrome/browser/prefs/pref_value_map.cc
@@ -102,6 +102,15 @@ void PrefValueMap::SetString(const std::string& key,
   SetValue(key, Value::CreateStringValue(value));
 }
 
+bool PrefValueMap::GetInteger(const std::string& key, int* value) const {
+  const Value* stored_value = NULL;
+  return GetValue(key, &stored_value) && stored_value->GetAsInteger(value);
+}
+
+void PrefValueMap::SetInteger(const std::string& key, const int value) {
+  SetValue(key, Value::CreateIntegerValue(value));
+}
+
 void PrefValueMap::GetDifferingKeys(
     const PrefValueMap* other,
     std::vector<std::string>* differing_keys) const {