Implement ping_freshness for update_client.

components/update_client/update_checker.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 "components/update_client/update_checker.h"
 
 #include <stddef.h>
 
 #include <string>
 #include <vector>
@@ skipping 64 matching lines @@
     base::StringAppendF(&app, "appid=\"%s\" version=\"%s\"", item->id.c_str(),
                         item->component.version.GetString().c_str());
     if (!brand.empty())
       base::StringAppendF(&app, " brand=\"%s\"", brand.c_str());
     if (item->on_demand)
       base::StringAppendF(&app, " installsource=\"ondemand\"");
     if (!ap.empty())
       base::StringAppendF(&app, " ap=\"%s\"", ap.c_str());
     base::StringAppendF(&app, ">");
     base::StringAppendF(&app, "<updatecheck />");
-    base::StringAppendF(&app, "<ping rd=\"%d\" />",
-                        metadata.GetDateLastRollCall(item->id));
+    base::StringAppendF(&app, "<ping rd=\"%d\" ping_freshnes=\"%s\" />",
+                        metadata.GetDateLastRollCall(item->id),
+                        metadata.GetPingFreshness(item->id).c_str());
     if (!item->component.fingerprint.empty()) {
       base::StringAppendF(&app,
                           "<packages>"
                           "<package fp=\"%s\"/>"
                           "</packages>",
                           item->component.fingerprint.c_str());
     }
     base::StringAppendF(&app, "</app>");
     app_elements.append(app);
     VLOG(1) << "Appending to update request: " << app;
@@ skipping 101 matching lines @@
 
 }  // namespace
 
 scoped_ptr<UpdateChecker> UpdateChecker::Create(
     const scoped_refptr<Configurator>& config,
     const PersistedData& persistent) {
   return scoped_ptr<UpdateChecker>(new UpdateCheckerImpl(config, persistent));
 }
 
 }  // namespace update_client