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

chrome/browser/chromeos/input_method/input_method_manager_impl.h

Index: chrome/browser/chromeos/input_method/input_method_manager_impl.h
diff --git a/chrome/browser/chromeos/input_method/input_method_manager_impl.h b/chrome/browser/chromeos/input_method/input_method_manager_impl.h
index 521e04aad54f7d4a69c7a246540c161c8d93293c..8f9f0a8ad8c1d0c2fdcdd26312e2898e40793be3 100644
--- a/chrome/browser/chromeos/input_method/input_method_manager_impl.h
+++ b/chrome/browser/chromeos/input_method/input_method_manager_impl.h
@@ -58,11 +58,15 @@ class InputMethodManagerImpl : public InputMethodManager,
       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(
@@ -95,6 +99,8 @@ class InputMethodManagerImpl : public InputMethodManager,
   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);
@@ -107,6 +113,18 @@ class InputMethodManagerImpl : public InputMethodManager,
   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;
@@ -165,6 +183,15 @@ class InputMethodManagerImpl : public InputMethodManager,
   // 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.
@@ -223,6 +250,9 @@ class InputMethodManagerImpl : public InputMethodManager,
 
   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);
 };