Revert 202926 "Change loading custom auth extension to load from..."

On suspicions that it turns four CrOS bots red.

TBR=tengs@chromium.org

Review URL: https://codereview.chromium.org/16210002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@202964 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/extensions/scoped_gaia_auth_extension.cc

@@ -34,14 +34,7 @@ void LoadGaiaAuthExtension(Profile* profile) {
   if (command_line->HasSwitch(switches::kAuthExtensionPath)) {
     base::FilePath auth_extension_path =
         command_line->GetSwitchValuePath(switches::kAuthExtensionPath);
-    const std::string extension_id =
-        component_loader->AddOrReplace(auth_extension_path);
-
-    if (extension_id.empty()) {
-        LOG(ERROR) << "Failed to load custom Gaia auth extension given by the "
-            << switches::kAuthExtensionPath << " flag: "
-            << auth_extension_path.value();
-    }
+    component_loader->Add(IDR_GAIA_TEST_AUTH_MANIFEST, auth_extension_path);
     return;
   }