Install and launch kiosk app from cached crx file at start up.

chrome/browser/chromeos/extensions/external_cache.h

Index: chrome/browser/chromeos/extensions/external_cache.h
diff --git a/chrome/browser/chromeos/extensions/external_cache.h b/chrome/browser/chromeos/extensions/external_cache.h
index 4c0040e72f6f86c861a0e555957c9407c04778dc..756ebe02125744df08d53380c326ac7236fecf9d 100644
--- a/chrome/browser/chromeos/extensions/external_cache.h
+++ b/chrome/browser/chromeos/extensions/external_cache.h
@@ -103,6 +103,9 @@ class ExternalCache : public content::NotificationObserver,
   virtual bool GetExtensionExistingVersion(const std::string& id,
                                            std::string* version) OVERRIDE;
 
+  // Returns true if the extension with |id| is pending for update check.
+  bool IsExtensionPendingForUpdateCheck(const std::string& id);
+
   // Shut down the cache. The |callback| will be invoked when the cache has shut
   // down completely and there are no more pending file I/O operations.
   void Shutdown(const base::Closure& callback);
@@ -128,6 +131,12 @@ class ExternalCache : public content::NotificationObserver,
                     std::string* version);
 
  private:
+  enum ExtensionStatus {
+    DOWNLOAD_PENDING,
+    DOWNLOAD_SUCCEEDED,
+    DOWNLOAD_FAILED,
+  };
+
   // Notifies the that the cache has been updated, providing
   // extensions loader with an updated list of extensions.
   void UpdateExtensionLoader();
@@ -164,6 +173,9 @@ class ExternalCache : public content::NotificationObserver,
   // and that have a valid crx in the cache.
   scoped_ptr<base::DictionaryValue> cached_extensions_;
 
+  // <extension_id : status>: used for tracking extension download status.
+  std::map<std::string, ExtensionStatus> extensions_status_;
+
   // Used to download the extensions and to check for updates.
   scoped_ptr<extensions::ExtensionDownloader> downloader_;