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/magnifier/partial_magnification_controller.h"
+#include "ash/shell.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/singleton.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:
+  accessibility::ScreenMagnifierType GetScreenMagnifierType() OVERRIDE {
+    if (!profile_)
+      return accessibility::MAGNIFIER_OFF;
+
+    PrefService* prefs = profile_->GetPrefs();
+    if (!prefs)
+      return accessibility::MAGNIFIER_OFF;
+
+    return accessibility::ScreenMagnifierTypeFromName(
+        prefs->GetString(prefs::kScreenMagnifierType).c_str());
+  }
+
+  void SetScreenMagnifier(accessibility::ScreenMagnifierType type) OVERRIDE {
+    PrefService* prefs = profile_->GetPrefs();
+    if (prefs) {
+      std::string typeString = ScreenMagnifierNameFromType(type);
+      if (typeString != prefs->GetString(prefs::kScreenMagnifierType)) {
+        prefs->SetString(prefs::kScreenMagnifierType, typeString);
+        prefs->CommitPendingWrite();
+      }
+    }
+
+    ash::Shell::GetInstance()->magnification_controller()->SetEnabled(
+        type == accessibility::MAGNIFIER_FULL);
+    ash::Shell::GetInstance()->partial_magnification_controller()->SetEnabled(
+        type == accessibility::MAGNIFIER_PARTIAL);
+  }
+
+ private:
+  void SetProfile(Profile* profile) {
+    if (pref_change_registrar_) {
+      pref_change_registrar_.reset();
+    }
+
+    if (profile) {
+      pref_change_registrar_.reset(new PrefChangeRegistrar);
+      pref_change_registrar_->Init(profile->GetPrefs());
+      pref_change_registrar_->Add(
+          prefs::kScreenMagnifierType,
+          base::Bind(&MagnificationManagerImpl::UpdateMagnifierStatus,
+                     base::Unretained(this)));
+    }
+
+    profile_ = profile;
+    UpdateMagnifierStatus();
+  }
+
+  void UpdateMagnifierStatus() {
+    UserManager* manager = UserManager::Get();
+    if (!profile_) {
+      SetScreenMagnifier(accessibility::MAGNIFIER_OFF);
+    } else if (manager && !manager->IsSessionStarted()) {
+      SetScreenMagnifier(accessibility::MAGNIFIER_FULL);
+    } else {
+      accessibility::ScreenMagnifierType type = GetScreenMagnifierType();
+      SetScreenMagnifier(type);
+    }
+  }
+
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE {
+    switch (type) {
+      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() {
+  // Makes sure that this is not called more than once.
+  CHECK(!GetInstance());
+
+  return new MagnificationManagerImpl();
+}
+
+}  // namespace chromeos