Add the partial screen magnifier to Chrome OS.

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 03cfadd3efbdf0aea32993efab0dccd0aff607ad..fce3ef5874c5f93a72c35748c02a16bd8499ba37 100644
--- a/chrome/browser/chromeos/preferences.cc
+++ b/chrome/browser/chromeos/preferences.cc
@@ -102,16 +102,16 @@ void Preferences::RegisterUserPrefs(PrefService* prefs) {
                                false,
                                PrefService::UNSYNCABLE_PREF);
   }
-  if (prefs->FindPreference(prefs::kScreenMagnifierEnabled) == NULL) {
-    prefs->RegisterBooleanPref(prefs::kScreenMagnifierEnabled,
-                               false,
-                               PrefService::UNSYNCABLE_PREF);
-  }
   if (prefs->FindPreference(prefs::kScreenMagnifierScale) == NULL) {
     prefs->RegisterDoublePref(prefs::kScreenMagnifierScale,
                               std::numeric_limits<double>::min(),
                               PrefService::UNSYNCABLE_PREF);
   }
+  if (prefs->FindPreference(prefs::kScreenMagnifierType) == NULL) {
+    prefs->RegisterStringPref(prefs::kScreenMagnifierType,
+                              "",
+                              PrefService::UNSYNCABLE_PREF);
+  }
   if (prefs->FindPreference(prefs::kVirtualKeyboardEnabled) == NULL) {
     prefs->RegisterBooleanPref(prefs::kVirtualKeyboardEnabled,
                                false,