diff --git a/chrome/browser/extensions/install_tracker.h b/chrome/browser/extensions/install_tracker.h
index 9624000..88397af 100644
--- a/chrome/browser/extensions/install_tracker.h
+++ b/chrome/browser/extensions/install_tracker.h
@@ -5,12 +5,17 @@
 #ifndef CHROME_BROWSER_EXTENSIONS_INSTALL_TRACKER_H_
 #define CHROME_BROWSER_EXTENSIONS_INSTALL_TRACKER_H_
 
+#include <map>
+
 #include "base/observer_list.h"
 #include "base/prefs/pref_change_registrar.h"
+#include "base/scoped_observer.h"
+#include "chrome/browser/extensions/active_install_data.h"
 #include "chrome/browser/extensions/install_observer.h"
 #include "components/keyed_service/core/keyed_service.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
+#include "extensions/browser/extension_registry_observer.h"
 
 class Profile;
 
@@ -21,9 +26,11 @@
 namespace extensions {
 
 class ExtensionPrefs;
+class ExtensionRegistry;
 
 class InstallTracker : public KeyedService,
-                       public content::NotificationObserver {
+                       public content::NotificationObserver,
+                       public ExtensionRegistryObserver {
  public:
   InstallTracker(Profile* profile,
                  extensions::ExtensionPrefs* prefs);
@@ -34,6 +41,22 @@
   void AddObserver(InstallObserver* observer);
   void RemoveObserver(InstallObserver* observer);
 
+  // If an install is currently in progress for |extension_id|, returns details
+  // of the installation. This instance retains ownership of the returned
+  // pointer. Returns NULL if the extension is not currently being installed.
+  const ActiveInstallData* GetActiveInstall(
+      const std::string& extension_id) const;
+
+  // Registers an install initiated by the user to allow checking of duplicate
+  // installs. Download of the extension has not necessarily started.
+  // RemoveActiveInstall() must be called when install is complete regardless of
+  // success or failure. Consider using ScopedActiveInstall rather than calling
+  // this directly.
+  void AddActiveInstall(const ActiveInstallData& install_data);
+
+  // Deregisters an active install.
+  void RemoveActiveInstall(const std::string& extension_id);
+
   void OnBeginExtensionInstall(
       const InstallObserver::ExtensionInstallParams& params);
   void OnBeginExtensionDownload(const std::string& extension_id);
@@ -57,9 +80,20 @@
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
+  // ExtensionRegistryObserver implementation.
+  virtual void OnExtensionInstalled(content::BrowserContext* browser_context,
+                                    const Extension* extension,
+                                    bool is_update) OVERRIDE;
+
+  // Maps extension id to the details of an active install.
+  typedef std::map<std::string, ActiveInstallData> ActiveInstallsMap;
+  ActiveInstallsMap active_installs_;
+
   ObserverList<InstallObserver> observers_;
   content::NotificationRegistrar registrar_;
   PrefChangeRegistrar pref_change_registrar_;
+  ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver>
+      extension_registry_observer_;
 
   DISALLOW_COPY_AND_ASSIGN(InstallTracker);
 };