Disable sync for default apps

chrome/common/extensions/extension.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/common/extensions/extension.h"
 
 #include <ostream>
 
 #include "base/base64.h"
 #include "base/basictypes.h"
@@ skipping 3758 matching lines @@
         return SYNC_TYPE_APP;
 
     default:
       return SYNC_TYPE_NONE;
   }
 }
 
 bool Extension::IsSyncable() const {
   // TODO(akalin): Figure out if we need to allow some other types.
 
-  // We want to sync any extensions that are internal and the chrome web store.
-  return location() == Extension::INTERNAL ||
-      id() == extension_misc::kWebStoreAppId;
+  // Default apps are not synced because otherwise they will pollute profiles
+  // that don't already have them. Specially, if a user doesn't have default
+  // apps, creates a new profile (which get default apps) and then enables sync
+  // for it, then their profile everywhere gets the default apps.
+  bool is_syncable = (location() == Extension::INTERNAL &&
+      !was_installed_by_default());
+  // Sync the chrome web store to maintain its position on the new tab page.
+  is_syncable |= (id() ==  extension_misc::kWebStoreAppId);
+  return is_syncable;
 }
 
 bool Extension::ShouldDisplayInLauncher() const {
   // All apps should be displayed on the NTP except for the Cloud Print App.
   return is_app() && id() != extension_misc::kCloudPrintAppId;
 }
 
 bool Extension::InstallWarning::operator==(const InstallWarning& other) const {
   return format == other.format && message == other.message;
 }
@@ skipping 151 matching lines @@
 
 UpdatedExtensionPermissionsInfo::UpdatedExtensionPermissionsInfo(
     const Extension* extension,
     const PermissionSet* permissions,
     Reason reason)
     : reason(reason),
       extension(extension),
       permissions(permissions) {}
 
 }   // namespace extensions