Make pnacl install on demand when it is not already installed.

chrome/browser/component_updater/component_updater_service.h

 // 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.
 
 #ifndef CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UPDATER_SERVICE_H_
 #define CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UPDATER_SERVICE_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 135 matching lines @@
   // registered component, soon. If an update or check is already in progress,
   // returns |kInProgress|. The same component cannot be checked repeatedly
   // in a short interval either (returns |kError| if so).
   // There is no guarantee that the item will actually be updated,
   // since another item may be chosen to be updated. Since there is
   // no time guarantee, there is no notification if the item is not updated.
   // However, the ComponentInstaller should know if an update succeeded
   // via the Install() hook.
   virtual Status CheckForUpdateSoon(const CrxComponent& component) = 0;
 
+  virtual bool FindRegisteredComponent(const std::vector<uint8>& pk_hash,
+                                       CrxComponent* component) = 0;
+
+
   virtual ~ComponentUpdateService() {}
 };
 
 // Creates the component updater. You must pass a valid |config| allocated on
 // the heap which the component updater will own.
 ComponentUpdateService* ComponentUpdateServiceFactory(
     ComponentUpdateService::Configurator* config);
 
 #endif  // CHROME_BROWSER_COMPONENT_UPDATER_COMPONENT_UPDATER_SERVICE_H_