Reduce CPU usage for input method switching.

chrome/browser/chromeos/status/input_method_menu.h

 // Copyright (c) 2010 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_STATUS_INPUT_METHOD_MENU_H_
 #define CHROME_BROWSER_CHROMEOS_STATUS_INPUT_METHOD_MENU_H_
 #pragma once
 
 #include "app/menus/simple_menu_model.h"
 #include "chrome/browser/chromeos/cros/input_method_library.h"
@@ skipping 45 matching lines @@
   virtual void HighlightChangedTo(int index);
   virtual void ActivatedAt(int index);
   virtual void MenuWillShow();
 
   // views::ViewMenuDelegate implementation. Sub classes can override the method
   // to adjust the position of the menu.
   virtual void RunMenu(views::View* unused_source,
                        const gfx::Point& pt);
 
   // InputMethodLibrary::Observer implementation.
-  virtual void InputMethodChanged(InputMethodLibrary* obj);
-  virtual void ImePropertiesChanged(InputMethodLibrary* obj);
-  virtual void ActiveInputMethodsChanged(InputMethodLibrary* obj);
+  virtual void InputMethodChanged(
+      InputMethodLibrary* obj,
+      const InputMethodDescriptor& previous_input_method,
+      const InputMethodDescriptor& current_input_method,
+      size_t num_active_input_methods);
+  virtual void ActiveInputMethodsChanged(
+      InputMethodLibrary* obj,
+      const InputMethodDescriptor& current_input_method,
+      size_t num_active_input_methods);
+  virtual void PreferenceUpdateNeeded(
+    InputMethodLibrary* obj,
+    const InputMethodDescriptor& previous_input_method,
+    const InputMethodDescriptor& current_input_method);
 
   // NotificationObserver implementation.
   virtual void Observe(NotificationType type,
                        const NotificationSource& source,
                        const NotificationDetails& details);
 
   // Sets the minimum width of the dropdown menu.
   void SetMinimumWidth(int width);
 
   // Registers input method preferences for the login screen.
   static void RegisterPrefs(PrefService* local_state);
 
   // Returns a string for the indicator on top right corner of the Chrome
   // window. The method is public for unit tests.
   static std::wstring GetTextForIndicator(
       const InputMethodDescriptor& input_method);
 
   // Returns a string for the drop-down menu and the tooltip for the indicator.
   // The method is public for unit tests.
   static std::wstring GetTextForMenu(const InputMethodDescriptor& input_method);
 
  protected:
   // Parses |input_method| and then calls UpdateUI().
-  void UpdateUIFromInputMethod(const InputMethodDescriptor& input_method);
+  void UpdateUIFromInputMethod(const InputMethodDescriptor& input_method,
+                               size_t num_active_input_methods);
 
   // Rebuilds model and menu2 objects in preparetion to open the menu.
   void PrepareForMenuOpen();
 
   // Returns menu2 object for language menu.
   views::Menu2& input_method_menu() {
     return input_method_menu_;
   }
 
  private:
   // Updates UI of a container of the menu (e.g. the "US" menu button in the
   // status area). Sub classes have to implement the interface for their own UI.
-  virtual void UpdateUI(
-      const std::wstring& name, const std::wstring& tooltip) = 0;
+  virtual void UpdateUI(const std::string& input_method_id,  // e.g. "mozc"
+                        const std::wstring& name,  // e.g. "US", "INTL"
+                        const std::wstring& tooltip,
+                        size_t num_active_input_methods) = 0;
 
   // Sub classes have to implement the interface. This interface should return
   // true if the dropdown menu should show an item like "Customize languages
   // and input..." DOMUI.
   virtual bool ShouldSupportConfigUI() = 0;
 
   // Sub classes have to implement the interface which opens an UI for
   // customizing languages and input.
   virtual void OpenConfigUI() = 0;
 
@@ skipping 36 matching lines @@
   const bool is_browser_mode_;
   const bool is_screen_locker_mode_;
   const bool is_out_of_box_experience_mode_;
 
   DISALLOW_COPY_AND_ASSIGN(InputMethodMenu);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_STATUS_INPUT_METHOD_MENU_H_