Add a do_not_sync pref to ExtensionPrefs.

chrome/browser/extensions/extension_service.cc

 // Copyright (c) 2013 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/browser/extensions/extension_service.h"
 
 #include <algorithm>
 #include <iterator>
 #include <set>
 
@@ skipping 564 matching lines @@
   // details.
   if (extension && extension->from_bookmark())
     creation_flags |= Extension::FROM_BOOKMARK;
 
   if (extension && extension->was_installed_by_default())
     creation_flags |= Extension::WAS_INSTALLED_BY_DEFAULT;
 
   if (extension && extension->was_installed_by_oem())
     creation_flags |= Extension::WAS_INSTALLED_BY_OEM;
 
-  if (extension)
+  if (extension) {
     installer->set_is_ephemeral(extension_prefs_->IsEphemeralApp(id));
+    installer->set_install_flag(extensions::kInstallFlagDoNotSync,
+                                extension_prefs_->DoNotSync(id));
+  }
 
   installer->set_creation_flags(creation_flags);
 
   installer->set_delete_source(file_ownership_passed);
   installer->set_install_cause(extension_misc::INSTALL_CAUSE_UPDATE);
   installer->InstallCrx(extension_path);
 
   if (out_crx_installer)
     *out_crx_installer = installer.get();
 
@@ skipping 1943 matching lines @@
 }
 
 void ExtensionService::OnProfileDestructionStarted() {
   ExtensionIdSet ids_to_unload = registry_->enabled_extensions().GetIDs();
   for (ExtensionIdSet::iterator it = ids_to_unload.begin();
        it != ids_to_unload.end();
        ++it) {
     UnloadExtension(*it, UnloadedExtensionInfo::REASON_PROFILE_SHUTDOWN);
   }
 }