Full Screen Magnifier: Add MagnificationManager

chrome/browser/chromeos/accessibility/magnification_manager.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/magnification_manager.h"
+
+#include "ash/magnifier/magnification_controller.h"
+#include "ash/shell.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/singleton.h"
+#include "chrome/browser/api/prefs/pref_change_registrar.h"
+#include "chrome/browser/api/prefs/pref_member.h"
+#include "chrome/browser/chromeos/login/user_manager.h"
+#include "chrome/browser/prefs/pref_service.h"
+#include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/profiles/profile_manager.h"
+#include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/pref_names.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "content/public/browser/notification_service.h"
+
+namespace chromeos {
+
+class MagnificationManagerImpl : public MagnificationManager,
+                                 public content::NotificationObserver {
+ public:
+  MagnificationManagerImpl() {
+    DCHECK(!instance_);
+    instance_ = this;
+
+    registrar_.Add(this,
+                  chrome::NOTIFICATION_SESSION_STARTED,
+                  content::NotificationService::AllSources());
+    registrar_.Add(this,
+                  chrome::NOTIFICATION_PROFILE_CREATED,
+                  content::NotificationService::AllSources());
+    registrar_.Add(this,
+                  chrome::NOTIFICATION_LOGIN_WEBUI_VISIBLE,
+                  content::NotificationService::AllSources());
+
+    Profile* profile = ProfileManager::GetDefaultProfileOrOffTheRecord();
+    SetProfile(profile);
+  }
+  virtual ~MagnificationManagerImpl() {}
+
+  static MagnificationManagerImpl* GetInstance() {
+    return instance_;
+  }
+
+  // MagnificationManager implimentation:
+  bool IsEnabled() OVERRIDE {
+#if defined(USE_ASH)
+    return ash::Shell::GetInstance()->magnification_controller()->IsEnabled();
+#else
+    return false;
+#endif
+  }
+
+  void SetEnabled(bool enabled) OVERRIDE {
+#if defined(USE_ASH)

[DaveMoore, 2012/10/11 20:09:27]

Should there be a check here that it's not called in the non ash case?

[yoshiki, 2012/10/12 15:00:55]

Done.

+    ash::Shell::GetInstance()->magnification_controller()->SetEnabled(enabled);
+#endif
+  }
+
+ private:
+  void SetProfile(Profile* profile) {
+    if (pref_change_registrar_) {
+      pref_change_registrar_->Remove(prefs::kScreenMagnifierEnabled, this);
+      pref_change_registrar_.reset();
+    }
+
+    if (profile) {
+      pref_change_registrar_.reset(new PrefChangeRegistrar);
+      pref_change_registrar_->Init(profile->GetPrefs());
+      pref_change_registrar_->Add(prefs::kScreenMagnifierEnabled, this);
+    }
+
+    profile_ = profile;
+    UpdateMagnifierStatus();
+  }
+
+  void UpdateMagnifierStatus() {
+    UserManager* manager = UserManager::Get();
+    if (!profile_) {
+      SetEnabled(false);
+    } else if (manager && !manager->IsSessionStarted()) {
+      SetEnabled(true);
+    } else {
+      PrefService* pref_service = profile_->GetPrefs();
+      bool enabled = pref_service->GetBoolean(prefs::kScreenMagnifierEnabled);
+      SetEnabled(enabled);
+    }
+  }
+
+  // content::NotificationObserver implimentation:
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE {
+    switch (type) {
+      case chrome::NOTIFICATION_PREF_CHANGED: {
+        std::string pref = *content::Details<std::string>(details).ptr();
+        if (pref == prefs::kScreenMagnifierEnabled)
+          UpdateMagnifierStatus();
+        break;
+      }
+      case chrome::NOTIFICATION_LOGIN_WEBUI_VISIBLE:
+      case chrome::NOTIFICATION_SESSION_STARTED: {
+        Profile* profile = ProfileManager::GetDefaultProfileOrOffTheRecord();
+        SetProfile(profile);
+        break;
+      }
+    }
+  }
+
+  static MagnificationManagerImpl* instance_;
+
+  Profile* profile_;
+  content::NotificationRegistrar registrar_;
+  scoped_ptr<PrefChangeRegistrar> pref_change_registrar_;
+
+  friend struct DefaultSingletonTraits<MagnificationManagerImpl>;
+  DISALLOW_COPY_AND_ASSIGN(MagnificationManagerImpl);
+};
+
+MagnificationManagerImpl* MagnificationManagerImpl::instance_ = NULL;
+
+MagnificationManager* MagnificationManager::GetInstance() {
+  return MagnificationManagerImpl::GetInstance();
+}
+
+MagnificationManager* MagnificationManager::CreateInstance() {

[DaveMoore, 2012/10/11 20:09:27]

Please add a check that this isn't called more than once, or remove the comment
in the header that says it shouldn't be.

[yoshiki, 2012/10/12 15:00:55]

Done.

+  return new MagnificationManagerImpl();
+}
+
+}  // namespace chromeos