Consolidate the update_client serialization code.

components/update_client/protocol_builder.h

 // Copyright 2017 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.
 
 #ifndef COMPONENTS_UPDATE_CLIENT_PROTOCOL_BUILDER_H_
 #define COMPONENTS_UPDATE_CLIENT_PROTOCOL_BUILDER_H_
 
 #include <memory>
 #include <string>
 #include <vector>
 
 #include "components/update_client/component.h"
+#include "components/update_client/crx_downloader.h"
 #include "components/update_client/updater_state.h"
 
 namespace update_client {
 
 class Configurator;
 class PersistedData;
 
 // Builds an update check request for |components|. |additional_attributes| is
 // serialized as part of the <request> element of the request to customize it
 // with data that is not platform or component specific. For each |item|, a
@@ skipping 27 matching lines @@
 //         version="1.0" nextversion="2.0">
 //          <event eventtype="3" eventresult="1"/>
 //          <event eventtype="14\" eventresult="0" downloader="direct"
 //              "errorcode="-1" url="http://host1/path1" downloaded="123"
 //              "total="456"/>
 //    </app>
 // </request>
 std::string BuildEventPingRequest(const Configurator& config,
                                   const Component& component);
 
+// Returns a string representing one ping event for the update of a component.
+// The event type for this ping event is 3.
+std::string BuildUpdateCompleteEventElement(const Component& component);
+
+// Returns a string representing one ping event for the uninstall of a
+// component. The event type for this ping event is 4.
+std::string BuildUninstalledEventElement(const Component& component);
+
+// Returns a string representing a download complete event corresponding to
+// one download metrics instance. The event type for this ping event is 14.
+std::string BuildDownloadCompleteEventElement(
+    const CrxDownloader::DownloadMetrics& metrics);
+
 // An update protocol request starts with a common preamble which includes
 // version and platform information for Chrome and the operating system,
 // followed by a request body, which is the actual payload of the request.
 // For example:
 //
 // <?xml version="1.0" encoding="UTF-8"?>
 // <request protocol="3.0" version="chrome-32.0.1.0" prodversion="32.0.1.0"
 //        requestid="{7383396D-B4DD-46E1-9104-AAC6B918E792}"
 //        updaterchannel="canary" arch="x86" nacl_arch="x86-64"
 //        ADDITIONAL ATTRIBUTES>
@@ skipping 18 matching lines @@
     const std::string& lang,
     const std::string& os_long_name,
     const std::string& download_preference,
     const std::string& request_body,
     const std::string& additional_attributes,
     const std::unique_ptr<UpdaterState::Attributes>& updater_state_attributes);
 
 }  // namespace update_client
 
 #endif  // COMPONENTS_UPDATE_CLIENT_PROTOCOL_PARSER_H_