Don't register or use the DelegateExecute verb handler if it isn't present.

chrome/installer/util/install_util.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.
 //
 // This file declares utility functions for the installer. The original reason
 // for putting these functions in installer\util library is so that we can
 // separate out the critical logic and write unit tests for it.
 
 #ifndef CHROME_INSTALLER_UTIL_INSTALL_UTIL_H_
 #define CHROME_INSTALLER_UTIL_INSTALL_UTIL_H_
@@ skipping 72 matching lines @@
   // Returns true if the installation represented by the pair of |dist| and
   // |system_level| is a multi install.
   static bool IsMultiInstall(BrowserDistribution* dist, bool system_install);
 
   // Returns true if this is running setup process for Chrome SxS (as
   // indicated by the presence of --chrome-sxs on the command line) or if this
   // is running Chrome process from the Chrome SxS installation (as indicated
   // by either --chrome-sxs or the executable path).
   static bool IsChromeSxSProcess();
 
+  // Returns true if the Chrome installed at |chrome_exe| has a Windows shell
+  // DelegateExecute verb handler.
+  static bool HasDelegateExecuteHandler(BrowserDistribution* dist,
+                                        const string16& chrome_exe);
+
   // Deletes the registry key at path key_path under the key given by root_key.
   static bool DeleteRegistryKey(HKEY root_key, const std::wstring& key_path);
 
   // Deletes the registry value named value_name at path key_path under the key
   // given by reg_root.
   static bool DeleteRegistryValue(HKEY reg_root, const std::wstring& key_path,
                                   const std::wstring& value_name);
 
   // An interface to a predicate function for use by DeleteRegistryKeyIf and
   // DeleteRegistryValueIf.
@@ skipping 52 matching lines @@
 
   // Returns a string in the form YYYYMMDD of the current date.
   static std::wstring GetCurrentDate();
 
  private:
   DISALLOW_COPY_AND_ASSIGN(InstallUtil);
 };
 
 
 #endif  // CHROME_INSTALLER_UTIL_INSTALL_UTIL_H_