Fix a threading issue and modernize the use of scoped_refptr in the on-demand update checker.

chrome/browser/google/google_update_win.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_GOOGLE_GOOGLE_UPDATE_WIN_H_
 #define CHROME_BROWSER_GOOGLE_GOOGLE_UPDATE_WIN_H_
 
 #include "base/callback_forward.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
@@ skipping 76 matching lines @@
   UpdateCheckDelegate() {}
 };
 
 // Begins an asynchronous update check on |task_runner|. If a new version is
 // available and |install_update_if_possible| is true, the new version will be
 // automatically downloaded and installed. |elevation_window| is the window
 // which should own any necessary elevation UI. Methods on |delegate| will be
 // invoked on the caller's thread to provide feedback on the operation, with
 // messages localized to |locale| if possible.
 void BeginUpdateCheck(
-    const scoped_refptr<base::SingleThreadTaskRunner>& task_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
     const std::string& locale,
     bool install_update_if_possible,
     gfx::AcceleratedWidget elevation_window,
     const base::WeakPtr<UpdateCheckDelegate>& delegate);
 
 // A type of callback supplied by tests to provide a custom IGoogleUpdate3Web
 // implementation (see src/google_update/google_update_idl.idl).
 typedef base::Callback<HRESULT(base::win::ScopedComPtr<IGoogleUpdate3Web>*)>
     GoogleUpdate3ClassFactory;
 
 // For use by tests that wish to provide a custom IGoogleUpdate3Web
 // implementation independent of Google Update's.
 void SetGoogleUpdateFactoryForTesting(
     const GoogleUpdate3ClassFactory& google_update_factory);
 
 #endif  // CHROME_BROWSER_GOOGLE_GOOGLE_UPDATE_WIN_H_