Revert 285661 "Remove some dead app host code."

trunk/src/chrome/installer/setup/setup_main.cc

 // 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.
 
 #include "chrome/installer/setup/setup_main.h"
 
 #include <windows.h>
 #include <msi.h>
 #include <shellapi.h>
 #include <shlobj.h>
@@ skipping 1621 matching lines @@
         }
       } else if ((install_status == NEW_VERSION_UPDATED) ||
                  (install_status == IN_USE_UPDATED)) {
         const Product* chrome = installer_state.FindProduct(
             BrowserDistribution::CHROME_BROWSER);
         if (chrome != NULL) {
           DCHECK_NE(chrome_exe, base::string16());
           RemoveChromeLegacyRegistryKeys(chrome->distribution(), chrome_exe);
         }
       }
+
+      if (prefs.install_chrome_app_launcher() &&
+          InstallUtil::GetInstallReturnCode(install_status) == 0) {
+        std::string webstore_item(google_update::GetUntrustedDataValue(
+            kInstallFromWebstore));
+        if (!webstore_item.empty()) {
+          bool success = InstallFromWebstore(webstore_item);
+          VLOG_IF(1, !success) << "Failed to launch app installation.";
+        }
+      }
     }
   }
 
   // There might be an experiment (for upgrade usually) that needs to happen.
   // An experiment's outcome can include chrome's uninstallation. If that is
   // the case we would not do that directly at this point but in another
   // instance of setup.exe
   //
   // There is another way to reach this same function if this is a system
   // level install. See HandleNonInstallCmdLineOptions().
@@ skipping 180 matching lines @@
     // Note that we allow the status installer::UNINSTALL_REQUIRES_REBOOT
     // to pass through, since this is only returned on uninstall which is
     // never invoked directly by Google Update.
     return_code = InstallUtil::GetInstallReturnCode(install_status);
   }
 
   VLOG(1) << "Installation complete, returning: " << return_code;
 
   return return_code;
 }