Implement oauth token external handler checking.

chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc

Index: chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc
diff --git a/chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc b/chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc
index 683c6725f748039490d6d9a623e84e155ca35954..299058ba1812ff09fa0f0b401ce70bd6a5a3d5d9 100644
--- a/chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc
+++ b/chrome/browser/chromeos/login/users/fake_chrome_user_manager.cc
@@ -173,4 +173,16 @@ UserFlow* FakeChromeUserManager::GetDefaultUserFlow() const {
   return default_flow_.get();
 }
 
+bool FakeChromeUserManager::FindKnownUserPrefs(
+    const user_manager::UserID& user_id,
+    const base::DictionaryValue** out_value) {
+  return false;
+}
+
+void FakeChromeUserManager::UpdateKnownUserPrefs(
+    const user_manager::UserID& user_id,
+    const base::DictionaryValue& values,
+    bool clear) {
+}
+
 }  // namespace chromeos