Replace string16 with base::string16.

chrome/browser/chromeos/login/fake_supervised_user_manager.cc

Index: chrome/browser/chromeos/login/fake_supervised_user_manager.cc
diff --git a/chrome/browser/chromeos/login/fake_supervised_user_manager.cc b/chrome/browser/chromeos/login/fake_supervised_user_manager.cc
index 6310d9e80b61b8040caf4a347ebe3e3b29a1cdb7..c0c2b3452ea9c47740beecfc1779081736f13ddd 100644
--- a/chrome/browser/chromeos/login/fake_supervised_user_manager.cc
+++ b/chrome/browser/chromeos/login/fake_supervised_user_manager.cc
@@ -17,7 +17,7 @@ const User* FakeSupervisedUserManager::CreateUserRecord(
     const std::string& manager_id,
     const std::string& local_user_id,
     const std::string& sync_user_id,
-    const string16& display_name) {
+    const base::string16& display_name) {
   return NULL;
 }
 
@@ -26,7 +26,7 @@ std::string FakeSupervisedUserManager::GenerateUserId() {
 }
 
 const User* FakeSupervisedUserManager::FindByDisplayName(
-    const string16& display_name) const {
+    const base::string16& display_name) const {
   return NULL;
 }
 
@@ -42,7 +42,7 @@ std::string FakeSupervisedUserManager::GetUserSyncId(
 
 string16 FakeSupervisedUserManager::GetManagerDisplayName(
     const std::string& managed_user_id) const {
-  return string16();
+  return base::string16();
 }
 
 std::string FakeSupervisedUserManager::GetManagerUserId(