[remoting host] Add User-Agent to third-party cert validation requests.

remoting/host/token_validator_factory_impl.cc

Index: remoting/host/token_validator_factory_impl.cc
diff --git a/remoting/host/token_validator_factory_impl.cc b/remoting/host/token_validator_factory_impl.cc
index 972a4100b0e23199388550a76bec1d095a213986..3df08303a3ab1684b16db28a8d32a02da46809ed 100644
--- a/remoting/host/token_validator_factory_impl.cc
+++ b/remoting/host/token_validator_factory_impl.cc
@@ -17,6 +17,7 @@
 #include "base/memory/ptr_util.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_util.h"
+#include "base/strings/stringize_macros.h"
 #include "base/values.h"
 #include "crypto/random.h"
 #include "net/base/elements_upload_data_stream.h"
@@ -89,6 +90,16 @@ void TokenValidatorImpl::StartValidateRequest(const std::string& token) {
   request_ = request_context_getter_->GetURLRequestContext()->CreateRequest(
       third_party_auth_config_.token_validation_url, net::DEFAULT_PRIORITY,
       this);
+
+  // Set a user-agent for logging/auditing purposes.
+#if defined(GOOGLE_CHROME_BUILD)
+  #define APP_NAME "Chrome Remote Desktop"

[Sergey Ulanov, 2016/05/18 07:11:02]

Don't need to use #define here.
std::string app_name = "Chrome Remote Desktop";

[Lambros, 2016/05/18 18:49:44]

Done.

+#else
+  #define APP_NAME "Chromoting"
+#endif
+  request_->SetExtraRequestHeaderByName(net::HttpRequestHeaders::kUserAgent,
+                                        APP_NAME " " STRINGIZE(VERSION), true);

[Sergey Ulanov, 2016/05/18 07:11:02]

Add a check that VERSION is defined:
#ifndef VERSION
 #error
#endif

[Lambros, 2016/05/18 18:49:44]

Done. (git cl format removes indentation of #error)

+
   request_->SetExtraRequestHeaderByName(
       net::HttpRequestHeaders::kContentType,
       "application/x-www-form-urlencoded", true);