Add login screen locale and input method device policies

chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc

Index: chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
diff --git a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
index 6fc261635b5702fc6f6f8aaa455f02e76f745061..1e85b9c24cc271d406a638291871d05a8999ebe9 100644
--- a/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/login/signin_screen_handler.cc
@@ -231,6 +231,39 @@ static bool SetUserInputMethodImpl(
   return true;
 }
 
+void EnforcePolicyInputMethods(std::string user_input_method) {
+  chromeos::CrosSettings* cros_settings = chromeos::CrosSettings::Get();
+  const base::ListValue* login_screen_input_methods = nullptr;
+  if (!cros_settings->GetList(chromeos::kDeviceLoginScreenInputMethods,
+                              &login_screen_input_methods))
+    return;

[Shu Chen, 2017/02/07 02:47:09]

nit: wrap this by brackets {}.

[pmarko, 2017/02/07 10:44:09]

Done.

+
+  std::vector<std::string> allowed_input_methods;
+
+  // Add user's input method first so it is pre-selected.
+  if (!user_input_method.empty()) {
+    allowed_input_methods.push_back(user_input_method);
+  }
+
+  std::string input_method;
+  for (const auto& input_method_entry : *login_screen_input_methods) {
+    if (input_method_entry->GetAsString(&input_method)) {
+      allowed_input_methods.push_back(input_method);
+    }

[Shu Chen, 2017/02/07 02:47:09]

nit: no need these brackets.

[pmarko, 2017/02/07 10:44:09]

Done.

+  }
+  chromeos::input_method::InputMethodManager* imm =
+      chromeos::input_method::InputMethodManager::Get();
+  imm->GetActiveIMEState()->SetAllowedInputMethods(allowed_input_methods);
+}
+
+void StopEnforcingPolicyInputMethods() {
+  // Empty means all input methods are allowed
+  std::vector<std::string> allowed_input_methods;
+  chromeos::input_method::InputMethodManager* imm =
+      chromeos::input_method::InputMethodManager::Get();
+  imm->GetActiveIMEState()->SetAllowedInputMethods(allowed_input_methods);
+}
+
 }  // namespace
 
 // LoginScreenContext implementation ------------------------------------------
@@ -294,6 +327,12 @@ SigninScreenHandler::SigninScreenHandler(
       chromeos::input_method::InputMethodManager::Get()->GetImeKeyboard();
   if (keyboard)
     keyboard->AddObserver(this);
+  OnAllowedInputMethodsChanged();
+  allowed_input_methods_subscription_ =
+      chromeos::CrosSettings::Get()->AddSettingsObserver(
+          chromeos::kDeviceLoginScreenInputMethods,
+          base::Bind(&SigninScreenHandler::OnAllowedInputMethodsChanged,
+                     base::Unretained(this)));
 
   content::ServiceManagerConnection::GetForProcess()
       ->GetConnector()
@@ -312,6 +351,7 @@ SigninScreenHandler::~SigninScreenHandler() {
       chromeos::input_method::InputMethodManager::Get()->GetImeKeyboard();
   if (keyboard)
     keyboard->RemoveObserver(this);
+  StopEnforcingPolicyInputMethods();

[Shu Chen, 2017/02/07 02:47:09]

I'd like to understand about what will happen after this?
By the implementation of InputMethodMangerImpl, SetAllowedInputMethods(<empty>)
won't make any impact to the input method list.
If that is intentional, why we need to StopEnforcingPolicyInputMethods?

[pmarko, 2017/02/07 10:44:09]

After SetAllowedInputMethods(non_empty_vec), additional input methods can not be
enabled. Calling SetAllowedInputMethods(empty_vec) will not change the input
method list, but it will be possible to add additional input methods again
(using EnableInputMethod).

This is meant for consistency: If the InputMethodManager's State outlives
SigninScreenHandler, I think SigninScreenHandler should not leave input method
restrictions in place. That's why these are removed in the destructor.

   weak_factory_.InvalidateWeakPtrs();
   if (delegate_)
     delegate_->SetWebUIHandler(nullptr);
@@ -354,6 +394,8 @@ void SigninScreenHandler::SetUserInputMethod(
 
   const std::string input_method = GetUserLRUInputMethod(username);
 
+  EnforcePolicyInputMethods(input_method);
+
   if (!input_method.empty())
     succeed = SetUserInputMethodImpl(username, input_method, ime_state);
 
@@ -568,6 +610,7 @@ void SigninScreenHandler::RegisterMessages() {
   AddCallback("showLoadingTimeoutError",
               &SigninScreenHandler::HandleShowLoadingTimeoutError);
   AddCallback("focusPod", &SigninScreenHandler::HandleFocusPod);
+  AddCallback("noPodFocused", &SigninScreenHandler::HandleNoPodFocused);
   AddCallback("getPublicSessionKeyboardLayouts",
               &SigninScreenHandler::HandleGetPublicSessionKeyboardLayouts);
   AddCallback("getTouchViewState",
@@ -1387,6 +1430,8 @@ void SigninScreenHandler::HandleFocusPod(const AccountId& account_id) {
   if (!test_focus_pod_callback_.is_null())
     test_focus_pod_callback_.Run();
 
+  focused_pod_account_id_ = base::MakeUnique<AccountId>(account_id);
+
   const user_manager::User* user =
       user_manager::UserManager::Get()->FindUser(account_id);
   // |user| may be nullptr in kiosk mode or unit tests.
@@ -1408,6 +1453,11 @@ void SigninScreenHandler::HandleFocusPod(const AccountId& account_id) {
   }
 }
 
+void SigninScreenHandler::HandleNoPodFocused() {
+  focused_pod_account_id_.reset();
+  EnforcePolicyInputMethods(std::string());
+}
+
 void SigninScreenHandler::HandleGetPublicSessionKeyboardLayouts(
     const AccountId& account_id,
     const std::string& locale) {
@@ -1555,4 +1605,14 @@ void SigninScreenHandler::OnFeedbackFinished() {
   HandleResyncUserData();
 }
 
+void SigninScreenHandler::OnAllowedInputMethodsChanged() {
+  if (focused_pod_account_id_) {
+    std::string user_input_method =
+        GetUserLRUInputMethod(focused_pod_account_id_->GetUserEmail());
+    EnforcePolicyInputMethods(user_input_method);
+  } else {
+    EnforcePolicyInputMethods(std::string());
+  }
+}
+
 }  // namespace chromeos