Sync starting language and input method preferences

chrome/browser/chromeos/input_method/input_method_syncer.h

Index: chrome/browser/chromeos/input_method/input_method_syncer.h
diff --git a/chrome/browser/chromeos/input_method/input_method_syncer.h b/chrome/browser/chromeos/input_method/input_method_syncer.h
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+// Copyright 2014 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_SYNCER_H_
+#define CHROME_BROWSER_CHROMEOS_INPUT_METHOD_INPUT_METHOD_SYNCER_H_
+
+#include <string>
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/prefs/pref_member.h"
+#include "chrome/browser/prefs/pref_service_syncable_observer.h"
+#include "ui/base/ime/chromeos/input_method_manager.h"
+
+class PrefServiceSyncable;
+
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
+namespace chromeos {
+namespace input_method {
+
+// Helper class to handle syncing of language and input method preferences.
+// Changes to local preferences are handed up to the sync server. But Chrome OS
+// should not locally apply the corresponding preferences from the sync server,
+// except once: when the user first logs into the device.
+// Thus, the user's most recent changes to language and input method preferences
+// will be brought down when signing in to a new device but not in future syncs.
+class InputMethodSyncer : public PrefServiceSyncableObserver {
+ public:
+  InputMethodSyncer(
+      PrefServiceSyncable* prefs,
+      scoped_refptr<input_method::InputMethodManager::State> ime_state);
+  virtual ~InputMethodSyncer();
+
+  // Registers the syncable input method prefs.
+  static void RegisterProfilePrefs(
+      user_prefs::PrefRegistrySyncable* registry);
+
+  // Must be called after InputMethodSyncer is created.
+  void Initialize();
+
+ private:
+  // Adds the input methods from the syncable prefs to the device-local prefs.
+  // This should only be called once (after user's first sync) and only adds
+  // to, not removes from, the user's input method prefs.
+  void MergeSyncedPrefs();
+
+  // For the given input method pref, adds unique values from |synced_pref| to
+  // values in |pref|. The new values are converted from legacy engine IDs to
+  // input method IDs if necessary.
+  std::string AddSupportedInputMethodValues(
+      const std::string& pref,
+      const std::string& synced_pref,
+      const char* pref_name);
+
+  // Sets prefs::kLanguagePreferredLanguages and sets |merging_| to false.
+  void FinishMerge(const std::string& languages);
+
+  // Callback method for preference changes. Updates the syncable prefs using
+  // the local pref values.
+  void OnPreferenceChanged(const std::string& pref_name);
+
+  // PrefServiceSyncableObserver implementation.
+  void OnIsSyncingChanged() override;
+
+  StringPrefMember preferred_languages_;
+  StringPrefMember preload_engines_;
+  StringPrefMember enabled_extension_imes_;
+  // These are syncable variants which don't change the device settings. We can
+  // set these to keep track of the user's most recent choices. That way, after
+  // the initial sync, we can add the user's synced choices to the values that
+  // have already been chosen at OOBE.
+  StringPrefMember preferred_languages_syncable_;
+  StringPrefMember preload_engines_syncable_;
+  StringPrefMember enabled_extension_imes_syncable_;
+
+  PrefServiceSyncable* prefs_;
+  scoped_refptr<input_method::InputMethodManager::State> ime_state_;
+
+  // Used to ignore PrefChanged events while InputMethodManager is merging.
+  bool merging_;
+
+  base::WeakPtrFactory<InputMethodSyncer> weak_factory_;
+};
+
+}  // namespace input_method
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_INPUT_METHOD_INPUT_METHOD_SYNCER_H_