Display badge when new background page is installed.

Added BackgroundPageTracker which tracks which extensions/apps contain
background pages.
Added code to wrench menu/toolbar to display a badge when there is a new
background page added to the system.

BUG=59980
TEST=BackgroundPageTrackerTest

Review URL: http://codereview.chromium.org/5207002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@66997 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 95 insertions, 0 deletions

diff --git a/chrome/browser/background_page_tracker.h b/chrome/browser/background_page_tracker.h
new file mode 100644
index 0000000..2b3b90c
--- /dev/null
+++ b/chrome/browser/background_page_tracker.h
@@ -0,0 +1,95 @@
+// Copyright (c) 2010 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/singleton.h"
+#include "chrome/common/notification_observer.h"
+#include "chrome/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* GetSingleton();
+
+  // 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_