Do not reload account picker when device-local account policy changes

chrome/browser/chromeos/login/screens/user_selection_screen.h

Index: chrome/browser/chromeos/login/screens/user_selection_screen.h
diff --git a/chrome/browser/chromeos/login/screens/user_selection_screen.h b/chrome/browser/chromeos/login/screens/user_selection_screen.h
index 36ddcf725274be42fd01fd077eb0a30a6d571b58..b7832f9dbcb2792eafb84c5b63ab9ee730c3eafc 100644
--- a/chrome/browser/chromeos/login/screens/user_selection_screen.h
+++ b/chrome/browser/chromeos/login/screens/user_selection_screen.h
@@ -10,18 +10,26 @@
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
+#include "base/memory/weak_ptr.h"
 #include "base/timer/timer.h"
 #include "base/values.h"
+#include "chrome/browser/chromeos/policy/device_local_account_policy_service.h"

[Nikita (slow), 2014/07/30 09:27:58]

Would it be possible to encapsulate chrome/browser/chromeos/policy dependency
somehow and move it out of this class as much as possible so that it would be
trivial to extract UserSelectionScreen out of src/chrome even if Policy code
stays in src/chrome for now?

This is needed for login code refactoring for Athena. End goal is to extract as
much as possible while extracted components are not allowed to depend on
src/chrome.

[bartfab (slow), 2014/08/04 13:46:49]

I moved all policy-related code to a ChromeUserSelectionScreen subclass. The
base UserSelectionScreen is not getting any new dependencies anymore.

 #include "chrome/browser/signin/screenlock_bridge.h"
 #include "components/user_manager/user.h"
 #include "ui/wm/core/user_activity_observer.h"
 
+namespace policy {
+class DeviceLocalAccountPolicyBroker;
+}
+
 namespace chromeos {
 
 class LoginDisplayWebUIHandler;
 
 // This class represents User Selection screen: user pod-based login screen.
-class UserSelectionScreen : public wm::UserActivityObserver {
+class UserSelectionScreen
+    : public wm::UserActivityObserver,
+      public policy::DeviceLocalAccountPolicyService::Observer {
  public:
   UserSelectionScreen();
   virtual ~UserSelectionScreen();
@@ -50,6 +58,10 @@ class UserSelectionScreen : public wm::UserActivityObserver {
   // wm::UserActivityDetector implementation:
   virtual void OnUserActivity(const ui::Event* event) OVERRIDE;
 
+  // policy::DeviceLocalAccountPolicyService::Observer implementation:
+  virtual void OnPolicyUpdated(const std::string& user_id) OVERRIDE;
+  virtual void OnDeviceLocalAccountsChanged() OVERRIDE;
+
   // Fills |user_dict| with information about |user|.
   static void FillUserDictionary(
       user_manager::User* user,
@@ -62,7 +74,19 @@ class UserSelectionScreen : public wm::UserActivityObserver {
   static bool ShouldForceOnlineSignIn(const user_manager::User* user);
 
  private:
+  // Check whether the display name set by policy for a public session has
+  // changed and if so, notify the UI.
+  void CheckForPublicSessionDisplayNameChange(
+      policy::DeviceLocalAccountPolicyBroker* broker);
+
+  // Notify the UI that the display name for a public session has changed,
+  // taking the display name from the |User| owned by |UserManager|.
+  void SetPublicSessionDisplayName(const std::string& user_id);
+
   LoginDisplayWebUIHandler* handler_;
+  bool handler_initialized_;
+
+  policy::DeviceLocalAccountPolicyService* device_local_account_policy_service_;
 
   // Set of Users that are visible.
   user_manager::UserList users_;
@@ -70,6 +94,10 @@ class UserSelectionScreen : public wm::UserActivityObserver {
   // Whether to show guest login.
   bool show_guest_;
 
+  // Map from public session user IDs to their display names set by policy.
+  typedef std::map<std::string, std::string> DisplayNamesMap;
+  DisplayNamesMap public_session_display_names_;
+
   // Map of usernames to their current authentication type. If a user is not
   // contained in the map, it is using the default authentication type.
   std::map<std::string, ScreenlockBridge::LockHandler::AuthType>
@@ -78,6 +106,8 @@ class UserSelectionScreen : public wm::UserActivityObserver {
   // Timer for measuring idle state duration before password clear.
   base::OneShotTimer<UserSelectionScreen> password_clear_timer_;
 
+  base::WeakPtrFactory<UserSelectionScreen> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(UserSelectionScreen);
 };