We should switch the keyboard layout to the layout the user set according to

chrome/browser/chromeos/input_method/input_method_manager_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CHROME_BROWSER_CHROMEOS_INPUT_METHOD_INPUT_METHOD_MANAGER_IMPL_H_
 #define CHROME_BROWSER_CHROMEOS_INPUT_METHOD_INPUT_METHOD_MANAGER_IMPL_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 40 matching lines @@
   virtual void AddObserver(InputMethodManager::Observer* observer) OVERRIDE;
   virtual void AddCandidateWindowObserver(
       InputMethodManager::CandidateWindowObserver* observer) OVERRIDE;
   virtual void RemoveObserver(InputMethodManager::Observer* observer) OVERRIDE;
   virtual void RemoveCandidateWindowObserver(
       InputMethodManager::CandidateWindowObserver* observer) OVERRIDE;
   virtual scoped_ptr<InputMethodDescriptors>
       GetSupportedInputMethods() const OVERRIDE;
   virtual scoped_ptr<InputMethodDescriptors>
       GetActiveInputMethods() const OVERRIDE;
+  virtual const std::vector<std::string>& GetActiveInputMethodIds() const
+      OVERRIDE;
   virtual size_t GetNumActiveInputMethods() const OVERRIDE;
   virtual void EnableLayouts(const std::string& language_code,
                              const std::string& initial_layout) OVERRIDE;
   virtual bool EnableInputMethods(
       const std::vector<std::string>& new_active_input_method_ids) OVERRIDE;
+  virtual bool EnableInputMethod(const std::string& new_active_input_method_id)
+      OVERRIDE;
   virtual bool MigrateOldInputMethods(
       std::vector<std::string>* input_method_ids) OVERRIDE;
   virtual bool MigrateKoreanKeyboard(
       const std::string& keyboard_id,
       std::vector<std::string>* input_method_ids) OVERRIDE;
   virtual bool SetInputMethodConfig(
       const std::string& section,
       const std::string& config_name,
       const InputMethodConfigValue& value) OVERRIDE;
   virtual void ChangeInputMethod(const std::string& input_method_id) OVERRIDE;
@@ skipping 12 matching lines @@
   virtual bool SwitchToNextInputMethod() OVERRIDE;
   virtual bool SwitchToPreviousInputMethod() OVERRIDE;
   virtual bool SwitchInputMethod(const ui::Accelerator& accelerator) OVERRIDE;
   virtual InputMethodDescriptor GetCurrentInputMethod() const OVERRIDE;
   virtual InputMethodPropertyList
       GetCurrentInputMethodProperties() const OVERRIDE;
   virtual XKeyboard* GetXKeyboard() OVERRIDE;
   virtual InputMethodUtil* GetInputMethodUtil() OVERRIDE;
   virtual ComponentExtensionIMEManager*
       GetComponentExtensionIMEManager() OVERRIDE;
+  virtual bool IsLanguageFullLatinKeyboard(const std::string& lang) const

[Seigo Nonaka, 2013/07/11 09:43:56]

As I mentioned in crbug.com/152843, please consider to use IsKeyboardLayout
function instead.

If you feel bad for non-Latin keyboard on login screen like Russian keyboard,
please do as separate work. (I recommend getting advise from UX or i18n team's).

[Alexander Alekseev, 2013/07/12 20:10:49]

It has already been discussed a bit in
https://code.google.com/p/chromium/issues/detail?id=152843 . I think I'll add
people from UX & i18n there.

+      OVERRIDE;
 
   // Sets |ibus_controller_|.
   void SetIBusControllerForTesting(IBusController* ibus_controller);
   // Sets |candidate_window_controller_|.
   void SetCandidateWindowControllerForTesting(
       CandidateWindowController* candidate_window_controller);
   // Sets |xkeyboard_|.
   void SetXKeyboardForTesting(XKeyboard* xkeyboard);
   // Initialize |component_extension_manager_|.
   void InitializeComponentExtensionForTesting(
       scoped_ptr<ComponentExtensionIMEManagerDelegate> delegate);
 
+  // For fast lookup "whether this language is among
+  // listed in kFullLatinKeyboardLanguageList or not"
+  class TwoLetterLanguageCode {
+   public:
+    TwoLetterLanguageCode() : val(0) {}
+    TwoLetterLanguageCode(const char* lang);
+    bool operator<(const TwoLetterLanguageCode& r) const { return val < r.val; }
+
+   private:
+    uint16_t val;
+  };
+
  private:
   // IBusController overrides:
   virtual void PropertyChanged() OVERRIDE;
 
   // IBusDaemonController overrides:
   virtual void OnConnected() OVERRIDE;
   virtual void OnDisconnected() OVERRIDE;
 
 
   // CandidateWindowController::Observer overrides:
@@ skipping 38 matching lines @@
 
   // Called when the ComponentExtensionIMEManagerDelegate is initialized.
   void OnComponentExtensionInitialized(
       scoped_ptr<ComponentExtensionIMEManagerDelegate> delegate);
   void InitializeComponentExtension();
 
   // Loads necessary component extensions.
   // TODO(nona): Support dynamical unloading.
   void LoadNecessaryComponentExtensions();
 
+  // Adds new input method to given list if possible
+  bool EnableInputMethodImpl(
+      const std::string& input_method_id,
+      std::vector<std::string>& new_active_input_method_ids) const;
+
+  // Start or stop the system input method framework as needed.

[Seigo Nonaka, 2013/07/11 09:43:56]

nit: Starts or stops

[Alexander Alekseev, 2013/07/12 20:10:49]

Done.

+  // (after list of enabled input methods has been updated)
+  void ReconfigureIMFramework();
+
   scoped_ptr<InputMethodDelegate> delegate_;
 
   // The current browser status.
   State state_;
 
   // A list of objects that monitor the manager.
   ObserverList<InputMethodManager::Observer> observers_;
   ObserverList<CandidateWindowObserver> candidate_window_observers_;
 
   // The input method which was/is selected.
@@ skipping 38 matching lines @@
   // An object for switching XKB layouts and keyboard status like caps lock and
   // auto-repeat interval.
   scoped_ptr<XKeyboard> xkeyboard_;
 
   std::string pending_input_method_;
 
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<InputMethodManagerImpl> weak_ptr_factory_;
 
+  // Sorted vector of kFullLatinKeyboardLanguageList[] for fast lookup.
+  std::vector<TwoLetterLanguageCode> full_latin_keyboard_languages_;
+
   DISALLOW_COPY_AND_ASSIGN(InputMethodManagerImpl);
 };
 
 }  // namespace input_method
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_INPUT_METHOD_INPUT_METHOD_MANAGER_IMPL_H_