Add persisted preference for projection touch HUD

chrome/browser/chromeos/preferences.cc

Index: chrome/browser/chromeos/preferences.cc
diff --git a/chrome/browser/chromeos/preferences.cc b/chrome/browser/chromeos/preferences.cc
index ce2ada0d573442000225218d9c53dab772ec7663..eb1b8105d313784c07ce643ac33c8abb578a7db5 100644
--- a/chrome/browser/chromeos/preferences.cc
+++ b/chrome/browser/chromeos/preferences.cc
@@ -406,6 +406,11 @@ void Preferences::RegisterUserPrefs(
       prefs::kTermsOfServiceURL,
       "",
       user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+
+  registry->RegisterBooleanPref(
+      prefs::kTouchHudProjectionEnabled,
+      false,
+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
 }
 
 void Preferences::InitUserPrefs(PrefServiceSyncable* prefs) {
@@ -445,6 +450,8 @@ void Preferences::InitUserPrefs(PrefServiceSyncable* prefs) {
                                    prefs, callback);
   save_file_default_directory_.Init(prefs::kSaveFileDefaultDirectory,
                                     prefs, callback);
+  touch_hud_projection_enabled_.Init(prefs::kTouchHudProjectionEnabled,
+                                     prefs, callback);
   primary_mouse_button_right_.Init(prefs::kPrimaryMouseButtonRight,
                                    prefs, callback);
   preferred_languages_.Init(prefs::kLanguagePreferredLanguages,
@@ -699,6 +706,10 @@ void Preferences::NotifyPrefChanged(const std::string* pref_name) {
                           drive::util::ConvertToMyDriveNamespace(pref_path));
     }
   }
+  if (!pref_name || *pref_name == prefs::kTouchHudProjectionEnabled) {
+    const bool enabled = touch_hud_projection_enabled_.GetValue();
+    ash::Shell::GetInstance()->TouchHudProjectionEnabledChanged(enabled);

[sky, 2013/07/03 13:47:08]

Wouldn't all this be simpler if Shell had a
SetTouchHudProjectionEnabled(boolean); along with a delegate method
IsTouchUndProjectionEnabledChanged() ?

[mohsen, 2013/07/03 15:30:40]

Do you mean a SetTouchHudProjectionEnabled(boolean) in the preference side to be
called from the Ash side (through ShellDelegate) whenever user toggles
projection HUD on and off; and an IsTouchHudProjectionEnabledChanged() in the
Ash side to be called from the preferences side to notify Ash of changes in
preference? Then, we also need an IsTouchHudProjectionEnabled() in the
preference side to be called from the Ash side to get the current value of the
preference. Isn't it similar to current implementation? Or I'm misunderstanding
you!

+  }
 
   if (!pref_name || *pref_name == prefs::kLanguagePreferredLanguages) {
     // Unlike kLanguagePreloadEngines and some other input method