Implement UMA log throttling for cellular connections

components/data_use_measurement/content/data_use_measurement_unittest.cc

 // Copyright 2015 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/data_use_measurement/content/data_use_measurement.h"
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/test/histogram_tester.h"
 #include "build/build_config.h"
 #include "content/public/browser/resource_request_info.h"
 #include "net/base/network_change_notifier.h"
 #include "net/base/request_priority.h"
 #include "net/socket/socket_test_util.h"
 #include "net/url_request/url_request.h"
 #include "net/url_request/url_request_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
 #if defined(OS_ANDROID)
 #include "base/android/application_status_listener.h"
 #endif
 
 namespace data_use_measurement {
 
 class DataUseMeasurementTest : public testing::Test {
  public:
-  DataUseMeasurementTest() {
+  DataUseMeasurementTest()
+      : data_use_measurement_(metrics::UpdateUsagePrefCallbackType()) {
     // During the test it is expected to not have cellular connection.
     DCHECK(!net::NetworkChangeNotifier::IsConnectionCellular(
         net::NetworkChangeNotifier::GetConnectionType()));
   }
 
   // This function makes a user request and confirms that its effect is
   // reflected in proper histograms.
   void TestForAUserRequest(const std::string& target_dimension) {
     net::TestDelegate test_delegate;
     InitializeContext();
@@ skipping 103 matching lines @@
 // background and OS is Android.
 TEST_F(DataUseMeasurementTest, ApplicationStateTest) {
   data_use_measurement()->OnApplicationStateChangeForTesting(
       base::android::APPLICATION_STATE_HAS_STOPPED_ACTIVITIES);
   TestForAServiceRequest("Background.");
   TestForAUserRequest("Background.");
 }
 #endif
 
 }  // namespace data_use_measurement