[Extensions] Update sync unittests to use manifest v2

Update profile_signin_confirmation_helper_unittest.cc and
sync_extension_helper.cc to generate extensions with
manifest_version 2.

Bug: 816679
Change-Id: I302693e92b7925f900cd41b7fa3751a4a299a8cf
Reviewed-on: https://chromium-review.googlesource.com/1008624Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550187}

chrome/browser/sync/test/integration/sync_extension_helper.cc

@@ -338,6 +338,7 @@ scoped_refptr<Extension> CreateExtension(const base::FilePath& base_dir,
   const std::string& public_key = NameToPublicKey(name);
   source.SetString(extensions::manifest_keys::kPublicKey, public_key);
   source.SetString(extensions::manifest_keys::kVersion, "0.0.0.0");
+  source.SetInteger(extensions::manifest_keys::kManifestVersion, 2);
   switch (type) {
     case Manifest::TYPE_EXTENSION:
       // Do nothing.

chrome/browser/ui/sync/profile_signin_confirmation_helper_unittest.cc

@@ -107,6 +107,7 @@ static scoped_refptr<extensions::Extension> CreateExtension(
     extensions::Manifest::Location location) {
   base::DictionaryValue manifest;
   manifest.SetString(extensions::manifest_keys::kVersion, "1.0.0.0");
+  manifest.SetInteger(extensions::manifest_keys::kManifestVersion, 2);
   manifest.SetString(extensions::manifest_keys::kName, name);
   std::string error;
   scoped_refptr<extensions::Extension> extension =