Reverting this CL because it was committed before I gave the final LGTM.

chrome/browser/chromeos/accessibility/accessibility_util.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/accessibility/accessibility_util.h"
 
 #include <queue>
 
 #include "ash/high_contrast/high_contrast_controller.h"
 #include "ash/magnifier/magnification_controller.h"
 #include "ash/shell.h"
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/logging.h"
 #include "chrome/browser/accessibility/accessibility_extension_api.h"
 #include "chrome/browser/browser_process.h"
-#include "chrome/browser/chromeos/accessibility/magnification_manager.h"
 #include "chrome/browser/extensions/component_loader.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/file_reader.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/speech/extension_api/tts_extension_api_controller.h"
 #include "chrome/common/extensions/extension.h"
 #include "chrome/common/extensions/extension_messages.h"
 #include "chrome/common/extensions/extension_resource.h"
@@ skipping 142 matching lines @@
   PrefService* pref_service = g_browser_process->local_state();
   pref_service->SetBoolean(prefs::kHighContrastEnabled, enabled);
   pref_service->CommitPendingWrite();
 
 #if defined(USE_ASH)
   ash::Shell::GetInstance()->high_contrast_controller()->SetEnabled(enabled);
 #endif
 }
 
 void EnableScreenMagnifier(bool enabled) {
-  if (MagnificationManager::GetInstance())
-    MagnificationManager::GetInstance()->SetEnabled(enabled);
+  PrefService* pref_service = g_browser_process->local_state();
+  pref_service->SetBoolean(prefs::kScreenMagnifierEnabled, enabled);
+  pref_service->CommitPendingWrite();
+
+#if defined(USE_ASH)
+  ash::Shell::GetInstance()->magnification_controller()->SetEnabled(enabled);
+#endif
 }
 
 void EnableVirtualKeyboard(bool enabled) {
   PrefService* pref_service = g_browser_process->local_state();
   pref_service->SetBoolean(prefs::kVirtualKeyboardEnabled, enabled);
   pref_service->CommitPendingWrite();
 }
 
 void ToggleSpokenFeedback(content::WebUI* login_web_ui) {
   bool spoken_feedback_enabled = g_browser_process &&
@@ skipping 32 matching lines @@
   if (!g_browser_process) {
     return false;
   }
   PrefService* prefs = g_browser_process->local_state();
   bool high_contrast_enabled = prefs &&
       prefs->GetBoolean(prefs::kHighContrastEnabled);
   return high_contrast_enabled;
 }
 
 bool IsScreenMagnifierEnabled() {
-  return MagnificationManager::GetInstance() &&
-      MagnificationManager::GetInstance()->IsEnabled();
+  if (!g_browser_process) {
+    return false;
+  }
+  PrefService* prefs = g_browser_process->local_state();
+  bool enabled = prefs && prefs->GetBoolean(prefs::kScreenMagnifierEnabled);
+  return enabled;
 }
 
 void MaybeSpeak(const std::string& utterance) {
   if (IsSpokenFeedbackEnabled())
     Speak(utterance);
 }
 
 }  // namespace accessibility
 }  // namespace chromeos