Removed BackgroundPageTracker - less code = more happiness

BUG=80755
TEST=Install extensions with background pages, make sure View Background Pages wrench menu item has the correct count.

Review URL: http://codereview.chromium.org/6929001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@84152 0039d316-1c4b-4281-b951-d872f2087c98

10 files changed, 74 insertions, 531 deletions

diff --git a/chrome/browser/background_page_tracker.cc b/chrome/browser/background_page_tracker.cc
deleted file mode 100644
index de6c04d..0000000
--- a/chrome/browser/background_page_tracker.cc
+++ /dev/null
@@ -1,301 +0,0 @@
-// Copyright (c) 2011 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/background_page_tracker.h"
-
-#include <set>
-#include <string>
-#include <vector>
-
-#include "base/command_line.h"
-#include "base/utf_string_conversions.h"
-#include "base/values.h"
-#include "chrome/browser/background_application_list_model.h"
-#include "chrome/browser/background_contents_service.h"
-#include "chrome/browser/background_contents_service_factory.h"
-#include "chrome/browser/background_mode_manager.h"
-#include "chrome/browser/browser_process.h"
-#include "chrome/browser/extensions/extension_service.h"
-#include "chrome/browser/prefs/pref_service.h"
-#include "chrome/browser/prefs/scoped_user_pref_update.h"
-#include "chrome/browser/profiles/profile.h"
-#include "chrome/browser/profiles/profile_manager.h"
-#include "chrome/common/extensions/extension.h"
-#include "chrome/common/pref_names.h"
-#include "content/common/notification_service.h"
-#include "content/common/notification_type.h"
-
-///////////////////////////////////////////////////////////////////////////////
-// BackgroundPageTracker keeps a single DictionaryValue (stored at
-// prefs::kKnownBackgroundPages). We keep only two pieces of information for
-// each background page: the parent application/extension ID, and a boolean
-// flag that is true if the user has acknowledged this page.
-//
-// kKnownBackgroundPages:
-//    DictionaryValue {
-//       <appid_1>: false,
-//       <appid_2>: true,
-//         ... etc ...
-//    }
-
-// static
-void BackgroundPageTracker::RegisterPrefs(PrefService* prefs) {
-  prefs->RegisterDictionaryPref(prefs::kKnownBackgroundPages);
-}
-
-// static
-BackgroundPageTracker* BackgroundPageTracker::GetInstance() {
-  return Singleton<BackgroundPageTracker>::get();
-}
-
-int BackgroundPageTracker::GetBackgroundPageCount() {
-  if (!IsEnabled())
-    return 0;
-
-  PrefService* prefs = GetPrefService();
-  const DictionaryValue* contents =
-      prefs->GetDictionary(prefs::kKnownBackgroundPages);
-  return contents ? contents->size() : 0;
-}
-
-int BackgroundPageTracker::GetUnacknowledgedBackgroundPageCount() {
-  if (!IsEnabled())
-    return 0;
-  PrefService* prefs = GetPrefService();
-  const DictionaryValue* contents =
-      prefs->GetDictionary(prefs::kKnownBackgroundPages);
-  if (!contents)
-    return 0;
-  int count = 0;
-  for (DictionaryValue::key_iterator it = contents->begin_keys();
-       it != contents->end_keys(); ++it) {
-    Value* value;
-    bool found = contents->GetWithoutPathExpansion(*it, &value);
-    DCHECK(found);
-    bool acknowledged = true;
-    bool valid = value->GetAsBoolean(&acknowledged);
-    DCHECK(valid);
-    if (!acknowledged)
-      count++;
-  }
-  return count;
-}
-
-void BackgroundPageTracker::AcknowledgeBackgroundPages() {
-  if (!IsEnabled())
-    return;
-  PrefService* prefs = GetPrefService();
-  DictionaryPrefUpdate update(prefs, prefs::kKnownBackgroundPages);
-  DictionaryValue* contents = update.Get();
-  bool prefs_modified = false;
-  for (DictionaryValue::key_iterator it = contents->begin_keys();
-       it != contents->end_keys(); ++it) {
-    contents->SetWithoutPathExpansion(*it, Value::CreateBooleanValue(true));
-    prefs_modified = true;
-  }
-  if (prefs_modified) {
-    prefs->ScheduleSavePersistentPrefs();
-    SendChangeNotification();
-  }
-}
-
-BackgroundPageTracker::BackgroundPageTracker() {
-  // If background mode is disabled, just exit - don't load information from
-  // prefs or listen for any notifications so we will act as if there are no
-  // background pages, effectively disabling any associated badging.
-  if (!IsEnabled())
-    return;
-
-  // Check to make sure all of the extensions are loaded - once they are loaded
-  // we can update the list.
-  Profile* profile = g_browser_process->profile_manager()->GetDefaultProfile();
-  if (profile->GetExtensionService() &&
-      profile->GetExtensionService()->is_ready()) {
-    UpdateExtensionList();
-    // We do not send any change notifications here, because the object was
-    // just created (it doesn't seem appropriate to send a change notification
-    // at initialization time). Also, since this is a singleton object, sending
-    // a notification in the constructor can lead to deadlock if one of the
-    // observers tries to get the singleton.
-  } else {
-    // Extensions aren't loaded yet - register to be notified when they are
-    // ready.
-    registrar_.Add(this, NotificationType::EXTENSIONS_READY,
-                   NotificationService::AllSources());
-  }
-}
-
-BackgroundPageTracker::~BackgroundPageTracker() {
-}
-
-PrefService* BackgroundPageTracker::GetPrefService() {
-  PrefService* service = g_browser_process->local_state();
-  DCHECK(service);
-  return service;
-}
-
-bool BackgroundPageTracker::IsEnabled() {
-  // Disable the background page tracker for unittests.
-  if (!g_browser_process->local_state())
-    return false;
-
-  // BackgroundPageTracker is enabled if background mode is enabled.
-  CommandLine* command_line = CommandLine::ForCurrentProcess();
-  return BackgroundModeManager::IsBackgroundModeEnabled(command_line);
-}
-
-void BackgroundPageTracker::Observe(NotificationType type,
-                                    const NotificationSource& source,
-                                    const NotificationDetails& details) {
-  switch (type.value) {
-    case NotificationType::EXTENSIONS_READY:
-      if (UpdateExtensionList())
-        SendChangeNotification();
-      break;
-    case NotificationType::BACKGROUND_CONTENTS_OPENED: {
-      std::string id = UTF16ToUTF8(
-          Details<BackgroundContentsOpenedDetails>(details)->application_id);
-      OnBackgroundPageLoaded(id);
-      break;
-    }
-    case NotificationType::EXTENSION_LOADED: {
-      const Extension* extension = Details<const Extension>(details).ptr();
-      if (!extension->is_hosted_app() &&
-          extension->background_url().is_valid())
-        OnBackgroundPageLoaded(extension->id());
-      break;
-    }
-    case NotificationType::EXTENSION_UNLOADED: {
-      std::string id = Details<UnloadedExtensionInfo>(details)->extension->id();
-      OnExtensionUnloaded(id);
-      break;
-    }
-    default:
-      NOTREACHED();
-  }
-}
-
-bool BackgroundPageTracker::UpdateExtensionList() {
-  // Extensions are loaded - update our list.
-  Profile* profile = g_browser_process->profile_manager()->GetDefaultProfile();
-  ExtensionService* extensions_service = profile->GetExtensionService();
-  DCHECK(extensions_service);
-
-  // We will make two passes to update the list:
-  // 1) Walk our list, and make sure that there's a corresponding extension for
-  //    each item in the list. If not, delete it (extension was uninstalled).
-  // 2) Walk the set of currently loaded extensions and background contents, and
-  //    make sure there's an entry in our list for each one. If not, create one.
-
-  PrefService* prefs = GetPrefService();
-  std::set<std::string> keys_to_delete;
-  bool pref_modified = false;
-  // If we've never set any prefs, then this is the first launch ever, so we
-  // want to automatically mark all existing extensions as acknowledged.
-  bool first_launch =
-      prefs->GetDictionary(prefs::kKnownBackgroundPages) == NULL;
-  DictionaryPrefUpdate update(prefs, prefs::kKnownBackgroundPages);
-  DictionaryValue* contents = update.Get();
-  for (DictionaryValue::key_iterator it = contents->begin_keys();
-       it != contents->end_keys(); ++it) {
-    // Check to make sure that the parent extension is still enabled.
-    const Extension* extension = extensions_service->GetExtensionById(
-        *it, false);
-    // If the extension is not loaded, add the id to our list of keys to delete
-    // later (can't delete now since we're still iterating).
-    if (!extension) {
-      keys_to_delete.insert(*it);
-      pref_modified = true;
-    }
-  }
-
-  for (std::set<std::string>::const_iterator iter = keys_to_delete.begin();
-       iter != keys_to_delete.end();
-       ++iter) {
-    contents->RemoveWithoutPathExpansion(*iter, NULL);
-  }
-
-  // Look for new extensions/background contents.
-  const ExtensionList* list = extensions_service->extensions();
-  for (ExtensionList::const_iterator iter = list->begin();
-       iter != list->begin();
-       ++iter) {
-    // Any extension with a background page should be in our list.
-    if ((*iter)->background_url().is_valid()) {
-      // If we have not seen this extension ID before, add it to our list.
-      if (!contents->HasKey((*iter)->id())) {
-        contents->SetWithoutPathExpansion(
-            (*iter)->id(), Value::CreateBooleanValue(first_launch));
-        pref_modified = true;
-      }
-    }
-  }
-
-  // Add all apps with background contents also.
-  BackgroundContentsService* background_contents_service =
-      BackgroundContentsServiceFactory::GetForProfile(profile);
-  std::vector<BackgroundContents*> background_contents =
-      background_contents_service->GetBackgroundContents();
-  for (std::vector<BackgroundContents*>::const_iterator iter =
-           background_contents.begin();
-       iter != background_contents.end();
-       ++iter) {
-     std::string application_id = UTF16ToUTF8(
-         background_contents_service->GetParentApplicationId(*iter));
-     if (!contents->HasKey(application_id)) {
-        contents->SetWithoutPathExpansion(
-            application_id, Value::CreateBooleanValue(first_launch));
-        pref_modified = true;
-     }
-  }
-
-  // Register for when new pages are loaded/unloaded so we can update our list.
-  registrar_.Add(this, NotificationType::EXTENSION_LOADED,
-                 NotificationService::AllSources());
-  registrar_.Add(this, NotificationType::EXTENSION_UNLOADED,
-                 NotificationService::AllSources());
-  registrar_.Add(this, NotificationType::BACKGROUND_CONTENTS_OPENED,
-                 NotificationService::AllSources());
-
-  // If we modified the list, save it to prefs and let our caller know.
-  if (pref_modified)
-    prefs->ScheduleSavePersistentPrefs();
-  return pref_modified;
-}
-
-void BackgroundPageTracker::OnBackgroundPageLoaded(const std::string& id) {
-  DCHECK(IsEnabled());
-  PrefService* prefs = GetPrefService();
-  DictionaryPrefUpdate update(prefs, prefs::kKnownBackgroundPages);
-  DictionaryValue* contents = update.Get();
-  // No need to update our list if this extension was already known.
-  if (contents->HasKey(id))
-    return;
-
-  // Update our list with this new as-yet-unacknowledged page.
-  contents->SetWithoutPathExpansion(id, Value::CreateBooleanValue(false));
-  prefs->ScheduleSavePersistentPrefs();
-  SendChangeNotification();
-}
-
-void BackgroundPageTracker::OnExtensionUnloaded(const std::string& id) {
-  DCHECK(IsEnabled());
-  PrefService* prefs = GetPrefService();
-  DictionaryPrefUpdate update(prefs, prefs::kKnownBackgroundPages);
-  DictionaryValue* contents = update.Get();
-
-  if (!contents->HasKey(id))
-    return;
-
-  contents->RemoveWithoutPathExpansion(id, NULL);
-  prefs->ScheduleSavePersistentPrefs();
-  SendChangeNotification();
-}
-
-void BackgroundPageTracker::SendChangeNotification() {
-  NotificationService::current()->Notify(
-      NotificationType::BACKGROUND_PAGE_TRACKER_CHANGED,
-      Source<BackgroundPageTracker>(this),
-      NotificationService::NoDetails());
-}
diff --git a/chrome/browser/background_page_tracker.h b/chrome/browser/background_page_tracker.h
deleted file mode 100644
index e00f5eb..0000000
--- a/chrome/browser/background_page_tracker.h
+++ /dev/null
@@ -1,95 +0,0 @@
-// Copyright (c) 2011 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.
-
-#ifndef CHROME_BROWSER_BACKGROUND_PAGE_TRACKER_H_
-#define CHROME_BROWSER_BACKGROUND_PAGE_TRACKER_H_
-#pragma once
-
-#include <map>
-#include <string>
-
-#include "base/gtest_prod_util.h"
-#include "base/memory/singleton.h"
-#include "content/common/notification_observer.h"
-#include "content/common/notification_registrar.h"
-
-class PrefService;
-
-///////////////////////////////////////////////////////////////////////////////
-// BackgroundPageTracker
-//
-// This class is a singleton class that monitors when new background pages are
-// loaded, and sends out a notification.
-//
-class BackgroundPageTracker : public NotificationObserver {
- public:
-  static void RegisterPrefs(PrefService* prefs);
-
-  // Convenience routine which gets the singleton object.
-  static BackgroundPageTracker* GetInstance();
-
-  // Returns the number of background apps/extensions currently loaded.
-  int GetBackgroundPageCount();
-
-  // Returns the number of unacknowledged background pages (for use in badges,
-  // etc).
-  int GetUnacknowledgedBackgroundPageCount();
-
-  // Called when the user has acknowledged that new background apps have been
-  // loaded. Future calls to GetUnacknowledgedBackgroundPageCount() will return
-  // 0 until another background page is installed.
-  void AcknowledgeBackgroundPages();
-
- protected:
-  // Constructor marked as protected so we can create mock subclasses.
-  BackgroundPageTracker();
-  ~BackgroundPageTracker();
-  friend struct DefaultSingletonTraits<BackgroundPageTracker>;
-  friend class BackgroundPageTrackerTest;
-  FRIEND_TEST_ALL_PREFIXES(BackgroundPageTrackerTest, OnBackgroundPageLoaded);
-  FRIEND_TEST_ALL_PREFIXES(BackgroundPageTrackerTest,
-                           AcknowledgeBackgroundPages);
-  FRIEND_TEST_ALL_PREFIXES(BackgroundPageTrackerTest,
-                           TestTrackerChangedNotifications);
-
-  // Mockable method to get the PrefService where we store information about
-  // background pages.
-  virtual PrefService* GetPrefService();
-
-  // Helper routine which checks to see if this object should be enabled or not.
-  // If false, the BackgroundPageTracker always acts as if there are no
-  // background pages. Virtual to allow enabling in mocks.
-  virtual bool IsEnabled();
-
- private:
-  // NotificationObserver implementation.
-  virtual void Observe(NotificationType type,
-                       const NotificationSource& source,
-                       const NotificationDetails& details);
-
-  // Invoked once all extensions have been loaded, so we can update our list of
-  // tracked pages and send out the appropriate notifications. Returns true if
-  // the extension list was changed.
-  bool UpdateExtensionList();
-
-  // Called when a background page is loaded (either because a hosted app
-  // opened a BackgroundContents or a packaged extension was loaded with an
-  // extension background page). Updates our internal list of unacknowledged
-  // background pages.
-  void OnBackgroundPageLoaded(const std::string& parent_application_id);
-
-  // When an extension is unloaded, removes it from the list of background pages
-  // so we no longer nag the user about it (if it is still unacknowledged) and
-  // we inform the user if it is ever re-installed/enabled.
-  void OnExtensionUnloaded(const std::string& parent_application_id);
-
-  // Sends out a notification that the list of background pages has changed.
-  void SendChangeNotification();
-
-  NotificationRegistrar registrar_;
-
-  DISALLOW_COPY_AND_ASSIGN(BackgroundPageTracker);
-};
-
-#endif  // CHROME_BROWSER_BACKGROUND_PAGE_TRACKER_H_
diff --git a/chrome/browser/background_page_tracker_unittest.cc b/chrome/browser/background_page_tracker_unittest.cc
deleted file mode 100644
index 40f33f5..0000000
--- a/chrome/browser/background_page_tracker_unittest.cc
+++ /dev/null
@@ -1,125 +0,0 @@
-// Copyright (c) 2011 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 "base/basictypes.h"
-#include "base/command_line.h"
-#include "base/utf_string_conversions.h"
-#include "chrome/browser/background_page_tracker.h"
-#include "chrome/test/testing_browser_process.h"
-#include "chrome/test/testing_browser_process_test.h"
-#include "chrome/test/testing_pref_service.h"
-#include "content/common/notification_service.h"
-#include "content/common/notification_type.h"
-#include "testing/gtest/include/gtest/gtest.h"
-#include "testing/platform_test.h"
-
-class MockBackgroundPageTracker : public BackgroundPageTracker {
- public:
-  MockBackgroundPageTracker() {
-    BackgroundPageTracker::RegisterPrefs(&prefs_);
-  }
-  ~MockBackgroundPageTracker() {}
-  // Overridden from BackgroundPageTracker to mock out functionality.
-  virtual bool IsEnabled() { return true; }
-  virtual PrefService* GetPrefService() { return &prefs_; }
- private:
-  TestingPrefService prefs_;
-};
-
-class BackgroundPageTrackerTest : public TestingBrowserProcessTest {
-};
-
-TEST_F(BackgroundPageTrackerTest, Create) {
-  MockBackgroundPageTracker tracker;
-  EXPECT_EQ(0, tracker.GetBackgroundPageCount());
-  EXPECT_EQ(0, tracker.GetUnacknowledgedBackgroundPageCount());
-}
-
-TEST_F(BackgroundPageTrackerTest, OnBackgroundPageLoaded) {
-  MockBackgroundPageTracker tracker;
-  EXPECT_EQ(0, tracker.GetBackgroundPageCount());
-  EXPECT_EQ(0, tracker.GetUnacknowledgedBackgroundPageCount());
-  std::string app1 = "app_id_1";
-  std::string app2 = "app_id_2";
-  tracker.OnBackgroundPageLoaded(app1);
-  EXPECT_EQ(1, tracker.GetBackgroundPageCount());
-  EXPECT_EQ(1, tracker.GetUnacknowledgedBackgroundPageCount());
-  tracker.OnBackgroundPageLoaded(app1);
-  EXPECT_EQ(1, tracker.GetBackgroundPageCount());
-  EXPECT_EQ(1, tracker.GetUnacknowledgedBackgroundPageCount());
-  tracker.OnBackgroundPageLoaded(app2);
-  EXPECT_EQ(2, tracker.GetBackgroundPageCount());
-  EXPECT_EQ(2, tracker.GetUnacknowledgedBackgroundPageCount());
-
-  tracker.OnExtensionUnloaded(app1);
-  EXPECT_EQ(1, tracker.GetBackgroundPageCount());
-  EXPECT_EQ(1, tracker.GetUnacknowledgedBackgroundPageCount());
-
-  tracker.OnExtensionUnloaded(app2);
-  EXPECT_EQ(0, tracker.GetBackgroundPageCount());
-  EXPECT_EQ(0, tracker.GetUnacknowledgedBackgroundPageCount());
-}
-
-TEST_F(BackgroundPageTrackerTest, AcknowledgeBackgroundPages) {
-  MockBackgroundPageTracker tracker;
-  EXPECT_EQ(0, tracker.GetBackgroundPageCount());
-  EXPECT_EQ(0, tracker.GetUnacknowledgedBackgroundPageCount());
-  std::string app1 = "app_id_1";
-  tracker.OnBackgroundPageLoaded(app1);
-  EXPECT_EQ(1, tracker.GetBackgroundPageCount());
-  EXPECT_EQ(1, tracker.GetUnacknowledgedBackgroundPageCount());
-  tracker.AcknowledgeBackgroundPages();
-  EXPECT_EQ(1, tracker.GetBackgroundPageCount());
-  EXPECT_EQ(0, tracker.GetUnacknowledgedBackgroundPageCount());
-  tracker.OnBackgroundPageLoaded(app1);
-  EXPECT_EQ(1, tracker.GetBackgroundPageCount());
-  EXPECT_EQ(0, tracker.GetUnacknowledgedBackgroundPageCount());
-}
-
-class BadgeChangedNotificationCounter : public NotificationObserver {
- public:
-  BadgeChangedNotificationCounter()
-      : count_(0) {
-    registrar_.Add(this,
-                   NotificationType::BACKGROUND_PAGE_TRACKER_CHANGED,
-                   NotificationService::AllSources());
-  }
-  // # notifications received.
-  int count() { return count_; }
-  // NotificationObserver implementation.
-  virtual void Observe(NotificationType type,
-                       const NotificationSource& source,
-                       const NotificationDetails& details) {
-    EXPECT_EQ(type.value,
-              NotificationType::BACKGROUND_PAGE_TRACKER_CHANGED);
-    count_++;
-  }
- private:
-  int count_;
-  NotificationRegistrar registrar_;
-};
-
-TEST_F(BackgroundPageTrackerTest, TestTrackerChangedNotifications) {
-  MockBackgroundPageTracker tracker;
-  BadgeChangedNotificationCounter counter;
-  std::string app1 = "app_id_1";
-  std::string app2 = "app_id_2";
-  std::string app3 = "app_id_3";
-  // New extension should generate notification
-  tracker.OnBackgroundPageLoaded(app1);
-  EXPECT_EQ(1, counter.count());
-  // Same extension should not generate notification
-  tracker.OnBackgroundPageLoaded(app1);
-  EXPECT_EQ(1, counter.count());
-  // New extension should generate notification
-  tracker.OnBackgroundPageLoaded(app2);
-  EXPECT_EQ(2, counter.count());
-  // Acknowledging pages should generate notification.
-  tracker.AcknowledgeBackgroundPages();
-  EXPECT_EQ(3, counter.count());
-  tracker.OnBackgroundPageLoaded(app1);
-  EXPECT_EQ(3, counter.count());
-  tracker.OnBackgroundPageLoaded(app3);
-  EXPECT_EQ(4, counter.count());
-}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index 08879d1..43d6fa7 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -8,7 +8,6 @@
 #include "chrome/browser/autofill/autofill_manager.h"
 #include "chrome/browser/background_contents_service.h"
 #include "chrome/browser/background_mode_manager.h"
-#include "chrome/browser/background_page_tracker.h"
 #include "chrome/browser/bookmarks/bookmark_utils.h"
 #include "chrome/browser/browser_shutdown.h"
 #include "chrome/browser/content_settings/host_content_settings_map.h"
@@ -107,7 +106,6 @@ void RegisterLocalState(PrefService* local_state) {
   geolocation::RegisterPrefs(local_state);
   AutofillManager::RegisterBrowserPrefs(local_state);
   BackgroundModeManager::RegisterPrefs(local_state);
-  BackgroundPageTracker::RegisterPrefs(local_state);
   NotificationUIManager::RegisterPrefs(local_state);
   PrefProxyConfigService::RegisterPrefs(local_state);
   policy::CloudPolicySubsystem::RegisterPrefs(local_state);
diff --git a/chrome/browser/task_manager/task_manager.cc b/chrome/browser/task_manager/task_manager.cc
index 6bc6543..2acca11 100644
--- a/chrome/browser/task_manager/task_manager.cc
+++ b/chrome/browser/task_manager/task_manager.cc
@@ -12,7 +12,11 @@
 #include "base/string_util.h"
 #include "base/threading/thread.h"
 #include "base/utf_string_conversions.h"
+#include "chrome/browser/background_contents_service.h"
+#include "chrome/browser/background_contents_service_factory.h"
 #include "chrome/browser/browser_process.h"
+#include "chrome/browser/extensions/extension_host.h"
+#include "chrome/browser/extensions/extension_process_manager.h"
 #include "chrome/browser/net/url_request_tracking.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile_manager.h"
@@ -1002,3 +1006,52 @@ bool TaskManagerModel::GetAndCacheMemoryMetrics(
   memory_usage_map_.insert(std::make_pair(handle, *usage));
   return true;
 }
+
+namespace {
+
+// Counts the number of extension background pages associated with this profile.
+int CountExtensionBackgroundPagesForProfile(Profile* profile) {
+  int count = 0;
+  ExtensionProcessManager* manager = profile->GetExtensionProcessManager();
+  if (!manager)
+    return count;
+  for (ExtensionProcessManager::const_iterator iter = manager->begin();
+       iter != manager->end();
+       ++iter) {
+    if ((*iter)->GetRenderViewType() == ViewType::EXTENSION_BACKGROUND_PAGE)
+      count++;
+  }
+  return count;
+}
+
+}  // namespace
+
+// static
+int TaskManager::GetBackgroundPageCount() {
+  int count = 0;
+  ProfileManager* profile_manager = g_browser_process->profile_manager();
+  if (!profile_manager)  // Null when running unit tests.
+    return count;
+  std::vector<Profile*> profiles(profile_manager->GetLoadedProfiles());
+  for (std::vector<Profile*>::const_iterator iter = profiles.begin();
+       iter != profiles.end();
+       ++iter) {
+    Profile* profile = *iter;
+    // Count the number of Background Contents (background pages for hosted
+    // apps). Incognito windows do not support hosted apps, so just check the
+    // main profile.
+    BackgroundContentsService* background_contents_service =
+        BackgroundContentsServiceFactory::GetForProfile(profile);
+    if (background_contents_service)
+      count += background_contents_service->GetBackgroundContents().size();
+
+    // Count the number of extensions with background pages (including
+    // incognito).
+    count += CountExtensionBackgroundPagesForProfile(profile);
+    if (profile->HasOffTheRecordProfile()) {
+      count += CountExtensionBackgroundPagesForProfile(
+          profile->GetOffTheRecordProfile());
+    }
+  }
+  return count;
+}
diff --git a/chrome/browser/task_manager/task_manager.h b/chrome/browser/task_manager/task_manager.h
index e11f595..2b8d0a2 100644
--- a/chrome/browser/task_manager/task_manager.h
+++ b/chrome/browser/task_manager/task_manager.h
@@ -169,6 +169,11 @@ class TaskManager {
 
   void OpenAboutMemory();
 
+  // Returns the number of background pages that will be displayed in the
+  // TaskManager. Used by the wrench menu code to display a count of background
+  // pages in the "View Background Pages" menu item.
+  static int GetBackgroundPageCount();
+
  private:
   FRIEND_TEST_ALL_PREFIXES(TaskManagerTest, Basic);
   FRIEND_TEST_ALL_PREFIXES(TaskManagerTest, Resources);
diff --git a/chrome/browser/task_manager/task_manager_browsertest.cc b/chrome/browser/task_manager/task_manager_browsertest.cc
index 6d68ac7..5f9455e 100644
--- a/chrome/browser/task_manager/task_manager_browsertest.cc
+++ b/chrome/browser/task_manager/task_manager_browsertest.cc
@@ -147,6 +147,7 @@ IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, NoticeTabContentsChanges) {
 
 IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, NoticeBGContentsChanges) {
   EXPECT_EQ(0, model()->ResourceCount());
+  EXPECT_EQ(0, TaskManager::GetBackgroundPageCount());
 
   // Show the task manager. This populates the model, and helps with debugging
   // (you see the task manager).
@@ -167,14 +168,17 @@ IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, NoticeBGContentsChanges) {
                                   ASCIIToUTF16("background_page"),
                                   application_id);
   WaitForResourceChange(3);
+  EXPECT_EQ(1, TaskManager::GetBackgroundPageCount());
 
   // Close the background contents and verify that we notice.
   service->ShutdownAssociatedBackgroundContents(application_id);
   WaitForResourceChange(2);
+  EXPECT_EQ(0, TaskManager::GetBackgroundPageCount());
 }
 
 IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, KillBGContents) {
   EXPECT_EQ(0, model()->ResourceCount());
+  EXPECT_EQ(0, TaskManager::GetBackgroundPageCount());
 
   // Show the task manager. This populates the model, and helps with debugging
   // (you see the task manager).
@@ -197,6 +201,7 @@ IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, KillBGContents) {
   // Wait for the background contents process to finish loading.
   WaitForBackgroundContents();
   EXPECT_EQ(3, model()->ResourceCount());
+  EXPECT_EQ(1, TaskManager::GetBackgroundPageCount());
 
   // Kill the background contents process and verify that it disappears from the
   // model.
@@ -210,10 +215,12 @@ IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, KillBGContents) {
   }
   ASSERT_TRUE(found);
   WaitForResourceChange(2);
+  EXPECT_EQ(0, TaskManager::GetBackgroundPageCount());
 }
 
 IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, NoticeExtensionChanges) {
   EXPECT_EQ(0, model()->ResourceCount());
+  EXPECT_EQ(0, TaskManager::GetBackgroundPageCount());
 
   // Show the task manager. This populates the model, and helps with debugging
   // (you see the task manager).
@@ -227,10 +234,12 @@ IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, NoticeExtensionChanges) {
   ASSERT_TRUE(LoadExtension(
       test_data_dir_.AppendASCII("common").AppendASCII("background_page")));
   WaitForResourceChange(3);
+  EXPECT_EQ(1, TaskManager::GetBackgroundPageCount());
 
   // Unload extension to avoid crash on Windows (see http://crbug.com/31663).
   UnloadExtension(last_loaded_extension_id_);
   WaitForResourceChange(2);
+  EXPECT_EQ(0, TaskManager::GetBackgroundPageCount());
 }
 
 IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, NoticeExtensionTabs) {
@@ -339,6 +348,7 @@ IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, NoticeNotificationChanges) {
 }
 
 IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, KillExtension) {
+  EXPECT_EQ(0, TaskManager::GetBackgroundPageCount());
   // Show the task manager. This populates the model, and helps with debugging
   // (you see the task manager).
   browser()->window()->ShowTaskManager();
@@ -349,6 +359,7 @@ IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, KillExtension) {
   // Wait until we see the loaded extension in the task manager (the three
   // resources are: the browser process, New Tab Page, and the extension).
   WaitForResourceChange(3);
+  EXPECT_EQ(1, TaskManager::GetBackgroundPageCount());
 
   EXPECT_TRUE(model()->GetResourceExtension(0) == NULL);
   EXPECT_TRUE(model()->GetResourceExtension(1) == NULL);
@@ -357,6 +368,7 @@ IN_PROC_BROWSER_TEST_F(TaskManagerBrowserTest, KillExtension) {
   // Kill the extension process and make sure we notice it.
   TaskManager::GetInstance()->KillProcess(2);
   WaitForResourceChange(2);
+  EXPECT_EQ(0, TaskManager::GetBackgroundPageCount());
 }
 
 // Disabled, http://crbug.com/66957.
diff --git a/chrome/browser/ui/toolbar/wrench_menu_model.cc b/chrome/browser/ui/toolbar/wrench_menu_model.cc
index ea832ff..2007004 100644
--- a/chrome/browser/ui/toolbar/wrench_menu_model.cc
+++ b/chrome/browser/ui/toolbar/wrench_menu_model.cc
@@ -13,7 +13,6 @@
 #include "base/string_util.h"
 #include "base/utf_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
-#include "chrome/browser/background_page_tracker.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/defaults.h"
 #include "chrome/browser/prefs/pref_service.h"
@@ -21,6 +20,7 @@
 #include "chrome/browser/sync/profile_sync_service.h"
 #include "chrome/browser/sync/sync_ui_util.h"
 #include "chrome/browser/tabs/tab_strip_model.h"
+#include "chrome/browser/task_manager/task_manager.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/toolbar/encoding_menu_controller.h"
 #include "chrome/browser/upgrade_detector.h"
@@ -249,7 +249,7 @@ string16 WrenchMenuModel::GetLabelForCommandId(int command_id) const {
 #endif
     case IDC_VIEW_BACKGROUND_PAGES: {
       string16 num_background_pages = base::FormatNumber(
-          BackgroundPageTracker::GetInstance()->GetBackgroundPageCount());
+          TaskManager::GetBackgroundPageCount());
       return l10n_util::GetStringFUTF16(IDS_VIEW_BACKGROUND_PAGES,
                                         num_background_pages);
     }
@@ -329,8 +329,7 @@ bool WrenchMenuModel::IsCommandIdVisible(int command_id) const {
     return false;
 #endif
   } else if (command_id == IDC_VIEW_BACKGROUND_PAGES) {
-    BackgroundPageTracker* tracker = BackgroundPageTracker::GetInstance();
-    return tracker->GetBackgroundPageCount() > 0;
+    return TaskManager::GetBackgroundPageCount() > 0;
   }
   return true;
 }
@@ -466,7 +465,7 @@ void WrenchMenuModel::Build() {
 #endif
   AddItem(IDC_ABOUT, l10n_util::GetStringFUTF16(IDS_ABOUT, product_name));
   string16 num_background_pages = base::FormatNumber(
-      BackgroundPageTracker::GetInstance()->GetBackgroundPageCount());
+      TaskManager::GetBackgroundPageCount());
   AddItem(IDC_VIEW_BACKGROUND_PAGES, l10n_util::GetStringFUTF16(
       IDS_VIEW_BACKGROUND_PAGES, num_background_pages));
   AddItem(IDC_UPGRADE_DIALOG, l10n_util::GetStringFUTF16(
diff --git a/chrome/chrome_browser.gypi b/chrome/chrome_browser.gypi
index 8a13e1c..be11431 100644
--- a/chrome/chrome_browser.gypi
+++ b/chrome/chrome_browser.gypi
@@ -253,8 +253,6 @@
         'browser/background_mode_manager_linux.cc',
         'browser/background_mode_manager_mac.mm',
         'browser/background_mode_manager_win.cc',
-        'browser/background_page_tracker.cc',
-        'browser/background_page_tracker.h',
         'browser/bookmarks/base_bookmark_model_observer.cc',
         'browser/bookmarks/base_bookmark_model_observer.h',
         'browser/bookmarks/bookmark_codec.cc',
diff --git a/chrome/chrome_tests.gypi b/chrome/chrome_tests.gypi
index 1841bc0..ed473fc 100644
--- a/chrome/chrome_tests.gypi
+++ b/chrome/chrome_tests.gypi
@@ -1237,7 +1237,6 @@
         'browser/background_application_list_model_unittest.cc',
         'browser/background_contents_service_unittest.cc',
         'browser/background_mode_manager_unittest.cc',
-        'browser/background_page_tracker_unittest.cc',
         'browser/bookmarks/bookmark_codec_unittest.cc',
         'browser/bookmarks/bookmark_context_menu_controller_unittest.cc',
         'browser/bookmarks/bookmark_html_writer_unittest.cc',