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

chrome/browser/extensions/activity_log/ad_injection_unittest.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 "base/prefs/testing_pref_service.h"
 #include "base/time/time.h"
 #include "chrome/browser/extensions/activity_log/activity_actions.h"
 #include "components/rappor/byte_vector_utils.h"
 #include "components/rappor/proto/rappor_metric.pb.h"
 #include "components/rappor/rappor_service.h"
 #include "extensions/common/value_builder.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace extensions {
 
@@ skipping 20 matching lines @@
 class TestRapporService : public rappor::RapporService {
  public:
   TestRapporService();
   virtual ~TestRapporService();
 
   // Returns the active reports. This also clears the internal map of metrics
   // as a biproduct, so if comparing numbers of reports, the comparison should
   // be from the last time GetReports() was called (not from the beginning of
   // the test).
   rappor::RapporReports GetReports();
+
+ protected:
+  TestingPrefServiceSimple prefs_;
 };
 
-TestRapporService::TestRapporService() {
+TestRapporService::TestRapporService()
+  : rappor::RapporService(&prefs_) {
   // Initialize the RapporService for testing.
   SetCohortForTesting(0);
   SetSecretForTesting(rappor::HmacByteVectorGenerator::GenerateEntropyInput());
 }
 
 TestRapporService::~TestRapporService() {}
 
 rappor::RapporReports TestRapporService::GetReports() {
   rappor::RapporReports result;
   rappor::RapporService::ExportMetrics(&result);
@@ skipping 20 matching lines @@
   EXPECT_EQ(1, reports.report_size());
 
   scoped_refptr<Action> harmless_action =
       CreateAction("Location.replace", "", "");
   harmless_action->DidInjectAd(&rappor_service);
   reports = rappor_service.GetReports();
   EXPECT_EQ(0, reports.report_size());
 }
 
 }  // namespace extensions