Factor Chrome details out of update manifest fetching.

extensions/browser/updater/default_manifest_fetch_data_delegate.cc

+// Copyright 2014 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 "extensions/browser/updater/default_manifest_fetch_data_delegate.h"
+
+namespace extensions {
+
+DefaultManifestFetchDataDelegate::DefaultManifestFetchDataDelegate() {
+}
+
+DefaultManifestFetchDataDelegate::~DefaultManifestFetchDataDelegate() {
+}
+
+std::string DefaultManifestFetchDataDelegate::GetBaseQueryParams() {
+  return "";
+}
+
+bool DefaultManifestFetchDataDelegate::ShouldAlwaysCheckWebstore() {
+  return false;
+}
+
+std::string DefaultManifestFetchDataDelegate::GetBrandCode() {
+  return "";
+}
+
+std::string DefaultManifestFetchDataDelegate::GetPingParamsAndData(
+    const std::string& extension_id,
+    const ManifestFetchData::PingData& old_ping_data,
+    ManifestFetchData::PingData* new_ping_data) {
+  return "";
+}
+
+}  // namespace extensions