Add a mechanism for collecting Rappor samples on a daily interval.

components/metrics/daily_observer.cc

Index: components/metrics/daily_observer.cc
diff --git a/components/metrics/client_info.cc b/components/metrics/daily_observer.cc
similarity index 58%
copy from components/metrics/client_info.cc
copy to components/metrics/daily_observer.cc
index 57ad3947c1bd6b736b3acd2b3b15e20454f9f135..cfc0e11d24865ccd27f347b04622f9c98778cbc8 100644
--- a/components/metrics/client_info.cc
+++ b/components/metrics/daily_observer.cc
@@ -2,12 +2,14 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "components/metrics/client_info.h"
+#include "components/metrics/daily_observer.h"
 
 namespace metrics {
 
-ClientInfo::ClientInfo() : installation_date(0), reporting_enabled_date(0) {}
+DailyObserver::DailyObserver() {
+}
 
-ClientInfo::~ClientInfo() {}
+DailyObserver::~DailyObserver() {
+}
 
 }  // namespace metrics