Add an option in language settings for activating the IME menu.

chrome/browser/chromeos/preferences.cc

 // 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.
 
 #include "chrome/browser/chromeos/preferences.h"
 
 #include <vector>
 
 #include "ash/autoclick/autoclick_controller.h"
 #include "ash/display/display_manager.h"
@@ skipping 267 matching lines @@
   input_method::InputMethodSyncer::RegisterProfilePrefs(registry);
 
   registry->RegisterBooleanPref(
       prefs::kResolveTimezoneByGeolocation, true,
       user_prefs::PrefRegistrySyncable::SYNCABLE_PREF);
 
   registry->RegisterBooleanPref(prefs::kCaptivePortalAuthenticationIgnoresProxy,
                                 true);
 
   registry->RegisterBooleanPref(prefs::kForceMaximizeOnFirstRun, false);
+
+  registry->RegisterBooleanPref(prefs::kLangugaeImeMenuFlagEnabled,

[michaelpg, 2016/01/04 16:37:36]

why is the flag also preference? do any other flags do this?

the pref isn't actually set anywhere, further suggesting we don't need it.

[Azure Wei, 2016/01/05 06:48:03]

This preference was used in language_options.js, it has been changed with
loadTimeData now.

+                                chromeos::switches::ImeMenuEnabled());
+
+  registry->RegisterBooleanPref(prefs::kLangugaeImeMenuActivated, false);
 }
 
 void Preferences::InitUserPrefs(syncable_prefs::PrefServiceSyncable* prefs) {
   prefs_ = prefs;
 
   BooleanPrefMember::NamedChangeCallback callback =
       base::Bind(&Preferences::OnPreferenceChanged, base::Unretained(this));
 
   performance_tracing_enabled_.Init(prefs::kPerformanceTracingEnabled,
                                     prefs, callback);
@@ skipping 12 matching lines @@
                                    prefs, callback);
   touch_hud_projection_enabled_.Init(prefs::kTouchHudProjectionEnabled,
                                      prefs, callback);
   preload_engines_.Init(prefs::kLanguagePreloadEngines, prefs, callback);
   enabled_extension_imes_.Init(prefs::kLanguageEnabledExtensionImes,
                                prefs, callback);
   current_input_method_.Init(prefs::kLanguageCurrentInputMethod,
                              prefs, callback);
   previous_input_method_.Init(prefs::kLanguagePreviousInputMethod,
                               prefs, callback);
+  ime_menu_activated_.Init(prefs::kLangugaeImeMenuActivated, prefs, callback);
 
   xkb_auto_repeat_enabled_.Init(
       prefs::kLanguageXkbAutoRepeatEnabled, prefs, callback);
   xkb_auto_repeat_delay_pref_.Init(
       prefs::kLanguageXkbAutoRepeatDelay, prefs, callback);
   xkb_auto_repeat_interval_pref_.Init(
       prefs::kLanguageXkbAutoRepeatInterval, prefs, callback);
 
   wake_on_wifi_darkconnect_.Init(prefs::kWakeOnWifiDarkConnect, prefs,
                                  callback);
@@ skipping 245 matching lines @@
     std::string value(enabled_extension_imes_.GetValue());
 
     std::vector<std::string> split_values;
     if (!value.empty()) {
       split_values = base::SplitString(value, ",", base::TRIM_WHITESPACE,
                                        base::SPLIT_WANT_ALL);
     }
     ime_state_->SetEnabledExtensionImes(&split_values);
   }
 
+  if (pref_name == prefs::kLangugaeImeMenuActivated &&
+      (reason == REASON_PREF_CHANGED || reason == REASON_ACTIVE_USER_CHANGED)) {
+    const bool activated = ime_menu_activated_.GetValue();
+    if (activated)
+      DVLOG(1) << "IME menu is activated.";
+    else
+      DVLOG(1) << "IME menu is deactivated.";
+    // TODO(azurewei): Fire inputMethodPrivate API event.
+  }
+
   if (user_is_active) {
     system::InputDeviceSettings::Get()->UpdateTouchpadSettings(
         touchpad_settings);
     system::InputDeviceSettings::Get()->UpdateMouseSettings(mouse_settings);
   }
 
   if (user_is_primary_ && (reason != REASON_PREF_CHANGED ||
                            pref_name == prefs::kWakeOnWifiDarkConnect)) {
     int features = wake_on_wifi_darkconnect_.GetValue()
                        ? WakeOnWifiManager::WAKE_ON_WIFI_DARKCONNECT
@@ skipping 121 matching lines @@
   touch_hud_projection_enabled_.SetValue(enabled);
 }
 
 void Preferences::ActiveUserChanged(const user_manager::User* active_user) {
   if (active_user != user_)
     return;
   ApplyPreferences(REASON_ACTIVE_USER_CHANGED, "");
 }
 
 }  // namespace chromeos